Drisya G.
Chandran
,
N.
Ramkumar
and
Rima
Biswas
*
School of Chemical Engineering, Vellore Institute of Technology, Vellore – 632014, Tamil Nadu, India. E-mail: rima.biswas@vit.ac.in
First published on 23rd January 2026
Graphyne-based materials (GBMs) have emerged as a versatile and promising class of carbon nanomaterials, featuring mixed sp- and sp2-hybridized carbon atoms, and have garnered considerable attention in recent years owing to their unique electronic structures, tunable pore architectures, and exceptional mechanical and chemical stability. These distinct characteristics make them suitable for a broad spectrum of applications, including water purification, hydrogen storage, nanoelectronics, sensing, and catalysis. This review critically examines recent advances in GBMs from both experimental and theoretical perspectives. We highlight the synthesis methods, different structural properties, and diverse applications of GBMs, along with insights from density functional theory (DFT) calculations and molecular dynamics (MD) simulations. Advances in molecular modeling, particularly DFT, have provided an atomic-level understanding of the electronic structure, adsorption energetics, and reaction mechanisms, while MD simulations have provided deep insights into the transport mechanisms, hydration effects, energy barriers, and interaction dynamics within GBM frameworks. The current challenges associated with large-scale synthesis, cost-effectiveness, long-range structural order, crystallinity, operational stability under diverse conditions, toxicity, and integration into practical systems are critically examined. Finally, future directions are proposed to guide the continued advancement and real-world implementation of GBMs. This review serves as a valuable resource for researchers and engineers involved in the design and development of next-generation GBMs for sustainable technological applications.
The escalating crisis of global water scarcity compounded by industrial pollution and climate change has intensified the demand for advanced water treatment and resource recovery technologies.10,11 Industrial sectors such as mining, petrochemicals, and agrochemicals continue to discharge heavy metals, persistent organics, and other hazardous contaminants into aquatic systems, posing acute risks to both environmental safety and human health.12 Considering that over 97% of the Earth's water exists as saline reserves, desalination has emerged as a critical strategy to augment freshwater supply.13,14 Conventional desalination techniques including multi-stage flash distillation and thermal vapor compression suffer from high capital expenditure and significant energy consumption.15,16 Membrane-based approaches, particularly reverse osmosis (RO), have gained market dominance due to their operational simplicity, scalability, and reduced carbon footprint.17–21 However, conventional polymeric membranes face intrinsic trade-offs between permeability and selectivity, as well as susceptibility to fouling and chemical degradation. These limitations have spurred intense research into nanostructured membrane materials capable of achieving high salt rejection rates, rapid water flux, and long-term operational stability.22,23 In this context, the atomic precision and inherent porosity of GY make it an ideal candidate for advanced separation platforms, as computational and experimental studies have shown superior ion rejection efficiencies and enhanced water permeability compared to conventional membranes.
Beyond water purification, GY's extended π-conjugation network and abundant active sites enable diverse applications in electrochemical energy storage, heterogeneous catalysis, and nanoelectronics.24 As anode materials for Li, Na, and K ion batteries, GY frameworks have demonstrated high theoretical capacities, fast ion diffusion kinetics, and structural robustness under repeated cycling.25,26 In catalysis, heteroatom-doped GY has exhibited remarkable activity for oxygen reduction reactions (ORRs), hydrogen evolution reactions (HERs), and CO2 reduction, in many cases surpassing conventional carbon catalysts in both turnover frequency and stability.24 Additionally, the tunable band gap and high carrier mobility render GY attractive for gas sensing, biosensing, and photodetection platforms.
Despite these promising prospects, large-scale synthesis of defect-free GY sheets remains a challenge, with current fabrication approaches such as cross-coupling polymerization, chemical vapor deposition (CVD), and on-surface synthesis yielding limited lateral dimensions and defect control. Here, computational materials science plays a decisive role in bridging the gap between theoretical potential and experimental realization.27 Density functional theory (DFT) and molecular dynamics (MD) simulations offer complementary insights, enabling predictive modeling of electronic structures, adsorption energetics, ionic transport dynamics, and mechanical resilience prior to synthesis. Density functional theory, a quantum-mechanical framework, has been indispensable in elucidating the fundamental energetics and electronic configurations of GY-based systems. For instance, Deb et al.28 proposed a novel carbon allotrope, pentagraphyne (PG-yne), and evaluated its potential as an anode material for Li and Na ion batteries using DFT calculations. Differential adsorption energy analysis indicated that PG-yne can accommodate up to eight Li or Na ions, achieving a high theoretical capacity of 680 mAh g−1. Similarly, a three-dimensional (3D) porous GY-based structure (3D-PGY) and a sandwich-type composite of graphene/PGY/graphene (G/PGY/G) were developed by Liu et al.29 When employed as the anode material for Li, Na, and K ion batteries, 3D-PGY delivers a theoretical specific capacity of about 558 mAh g−1. The corresponding average open-circuit voltages for Li, Na, and K ion storage are 0.48/0.52/0.29 V for 3D-PGY and 1.08/1.04/1.39 V for the G/PGY/G configuration. In hydrogen storage research, Singh et al.30 explored the hydrogen storage potential of zirconium (Zr)-decorated γ-GY monolayers using DFT and reported that each Zr atom anchored on the 2D γ-GY surface can adsorb up to seven H2 molecules, exhibiting an average adsorption energy of −0.44 eV per H2. This corresponds to a gravimetric hydrogen density of 7.95 wt% and a desorption temperature of 574 K, parameters well-suited for practical fuel-cell operation. Such studies exemplify how first-principles calculations can pinpoint optimal dopants, predict stable configurations, and quantify performance-limiting factors before experimental synthesis.
While DFT provides atomistic-level energy landscapes, it is inherently restricted in time and length scales.31 Classical MD simulations address this limitation by enabling the exploration of atomic trajectories over nanosecond to microsecond regimes, thus capturing the dynamic interplay between ions, molecules, and the GY matrix under realistic thermodynamic conditions. Majidi et al.32 leveraged MD simulations to examine the permeation behavior of Hg2+ and Cu2+, through functionalized pores of γ-GY-1 nanosheets under an external electric field. The electrostatic interactions between ions and the –NH2 group were stronger than those with the –COOH group, enabling the –NH2 pore to facilitate higher ion permeation across all applied electric fields. At a more computationally intensive level, ab initio molecular dynamics (AIMD) incorporates quantum effects into dynamic simulations, making it invaluable for modeling adsorption–desorption cycles, thermal stability, and structural relaxation at finite temperatures.33 Gao et al.34 explored the hydrogen storage capability of holey graphyne (HGY), which exhibits strong potential for energy storage applications. Employing DFT and AIMD simulations, the authors investigated Li-functionalized single-layer HGY for H2 storage. The DFT results indicated that Li atoms bind firmly to the HGY surface without exhibiting clustering tendencies, with each Li site capable of adsorbing up to four H2 molecules at an average adsorption energy of −0.22 eV per H2.
Previous reviews on GBMs have offered limited insights into their structural attributes, synthesis strategies, and functional applications,24,27,35–38 and the existing literature remains fragmented, particularly lacking comprehensive analyses that concurrently address first-principles insights and dynamic simulations of GY systems. The emerging novelty and versatility of GBMs warrant a more comprehensive and unified examination. In particular, integrating both MD and DFT approaches is essential to unravel their fundamental mechanisms and to establish GBMs as indispensable materials for advanced environmental remediation and sustainable technologies. The synergistic integration of DFT and MD methodologies provides a multi-scale computational framework capable of guiding the rational design of GBMs for targeted applications. Accordingly, this review aims to bridge existing knowledge gaps by delivering an in-depth discussion of the recent advances in GBMs, with particular emphasis on DFT- and MD-based studies. We begin by outlining the structural diversity and synthesis strategies, followed by an overview of the intrinsic properties of GBMs, and key application domains reported in the literature. Subsequently, we critically evaluate computational studies, highlighting case examples that demonstrate the predictive and diagnostic capabilities of atomistic simulations. Finally, we discuss the current challenges and future research perspectives aimed at translating the unique potential of GBMs from theoretical models to practical technologies.
Interestingly, a novel family of carbon allotropes known as “Graphynes” emerged, which are one-atom-thick planar sheets made up of phenyl rings joined by acetylene bonds (–C
C–). The existence of GY was hypothesized prior to the 1960s,39 but it garnered significant attention following the discovery of fullerenes. Theoretical investigations into GY structures have been actively pursued since the 1980s. In 1987, Baughman et al.40 described GY as a stable crystalline carbon allotrope with high degrees of sp hybridization, and it was named after graphite and ethyne because of the ethynyl units and aromatic moiety rings (which represent the sp- and sp2-hybridized carbon).41,42 The ratio of sp and sp2 hybridized bonds defines the kinds of GY structures, such as α-GY, β-GY, γ-GY, graphdiyne (GDY), graphtriyne (GTY), graphtetrayne (GTTY), and δ-GY (6,6,12-GY) (see Fig. 1a–j).43 They are referred to as GY-n based on the number of acetylene linkages and have a porosity of 18–25% caused by bonds between phenyl rings, giving GY an exciting future in ion permeation. Moreover, all allotropes of pristine GY contain intrinsic tunable holes, and they can perform well in ion rejection when compared to other nanoporous membranes.44
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| Fig. 1 Schematic of the structures of (a) GRA, (b) α-GY, (c) β-GY, (d) γ-GY, and γ-GY architectures: (e) γ-GY-1, (f) γ-GY-2, (g) γ-GY-3, (h) γ-GY-4, (i) γ-GY-5, and (j) δ-GY. | ||
The size of the pores within the GY structure can be modified by changing the number of acetylene bonds between the adjacent benzene rings.27 More specifically, GDY is a carbon allotrope featuring twin acetylenic groups with sp-hybridized acetylenic connections between neighbouring benzoic rings, which endow it with high π-conjugation. It was first suggested by Haley et al.45 in 1997 and is expected to be one of the most stable diacetylene-containing sp2 carbon compounds. Initial studies concentrated on the synthesis of GDY from structurally similar organic compounds and on the use of computational modeling of related materials to predict its fundamental properties.
The carbon–carbon triple bonds and uniformly distributed triangular pore structure of GDY provide numerous reactive sites and enable multiple reaction pathways, owing to its chemical decoration.46 The presence of two acetylenic linkages effectively doubles the length of the carbon chains connecting the hexagonal rings.47 Consequently, GDY does not retain the superior mechanical properties characteristic of GY. Graphdiyne exhibits a lower mechanical stiffness than that of GY and GRA, with an in-plane stiffness of 120 N m−1. This corresponds to a Young's modulus of approximately 375 GPa, assuming a nominal thickness of 0.320 nm. While GDY is classified within the GY family, its distinctive properties often warrant separate consideration in research and applications.47,48 Graphenylene is a 2D sp2-carbon network generated by the fusion of hexatomic rings and tetratomic rings. In 2011, Balaban and Vollhardt49 introduced the graphenylene structure. In recent times, graphenylene has received a lot of interest owing to its pore structure and thermodynamic stability. It has been employed as a membrane to separate gases, but not to desalinate water.50
Although the ideal atomic structures of GBMs elucidate the origin of their unique properties, their experimental realization is inherently governed by the feasibility of synthesis. The presence of sp–sp2 hybridized carbon frameworks imposes significant kinetic and thermodynamic constraints, directly influencing crystallinity, defect formation, and structural fidelity. Therefore, a critical assessment of synthesis strategies is essential to bridge idealized structural models with experimentally attainable GBMs. The following section reviews the available synthesis routes, emphasizing their structural limitations and practical challenges.
Furthermore, embracing unconventional strategies originating from diverse scientific fields could be pivotal in uncovering innovative and unprecedented synthetic routes. Early studies proposed that the controlled oligomerization of cyclocarbon could lead to the formation of γ-GY. Kehoe et al.53 created three dehydrobenzoannulenes (DBAs a, b, and c) using an intramolecular cyclization strategy. Subsequently, the DBAs d and e were synthesized by Yoshimura et al.54 using a combination of intramolecular bonding and double elimination. In 2008, Haley55 outlined synthetic strategies for constructing substructures of the non-natural, planar carbon network GDY, utilizing the dehydrobenzo56 annulene framework, and explored their optoelectronic properties. He further emphasized the critical need to extensively explore and employ metal-catalyzed cross-coupling, homocoupling, and metathesis reactions as key strategies for the successful synthesis of target GDY architectures. Advancing the synthesis of GY materials may involve utilizing surfaces as templates or scaffolds, similar to the strategies employed in the CVD of GRA from organic precursors on metal surfaces.57 The value of synthesizing extended GY materials largely hinges on the unique properties that they are expected to exhibit, especially their electronic behaviour. Prominent GBMs development timelines are shown in Fig. 2.
In 2010, γ-GDY was successfully synthesized on copper substrates via the Glaser–Hay cross-coupling reaction using hexaethynylbenzene as the precursor.58 Energy-dispersive X-ray spectroscopy (EDX) analysis indicates that the GDY film is composed exclusively of elemental carbon. The authors further utilized Raman spectroscopy to examine the structural uniformity and quality of the GDY film on copper foil and to verify the presence of characteristic carbon–carbon bonds predicted by its theoretical model. The results revealed the presence of both aromatic rings and carbon–carbon triple bonds, characteristic of the acetylenic linkages in GDY. These findings suggest the successful synthesis of GDY. The proposed approach enables the synthesis of nanometer-scale GDY and GTTY structures, albeit with limited long-range order. To further tailor the characteristics of GBMs for specific applications, researchers have investigated various functionalization strategies including substitution, heteroatom doping, and formation of GY-based nanocomposites. Initially, efforts were directed toward expanding the structural diversity of GY derivatives, leading to the first experimental synthesis of hydrogen-substituted graphyne (HsGY), which was accomplished by Deng and co-workers59 through cross-coupling polymerization between 1,3,5-triethynylbenzene and 1,3,5-tribromobenzene. Over time, the structural integrity and stability of nanoscale GDY remained unresolved.
In this context, Yuan and Ding60 systematically investigated the electronic and geometric structures of carbyne on various transition metal surfaces. They observed that on less reactive metals, carbyne adopts a polyynic structure, which tends to exhibit a curved geometry. In contrast, on catalytically active metal surfaces, carbyne prefers a linear polycumulenic configuration due to its greater stability. These structural preferences highlight the potential of metal-assisted self-assembly of carbyne as a strategic approach for the synthesis of GY.
Following these developments, the design and synthesis of GBMs have been extensively developed, enabling the creation of structures with different length scales.61–63 In these studies, the coupling reaction of acetylenes serves as a pivotal method for synthesizing novel GY-type molecules and materials. However, the resulting materials often exhibit strong aggregation tendencies, complicating the fabrication of thinner films necessary to reveal their intrinsic properties and broaden their application spectrum. Addressing this challenge requires the rational design and synthesis of precursors, the development of effective connection methodologies, and the construction of GYs and GDYs with precise topologies and controlled thicknesses. Therefore, this underscores the pressing need for innovative strategies to engineer GYs with diverse structural configurations for advanced technological applications. In response to the challenges associated with synthesizing GY materials with specific topologies and reduced aggregation, Wu et al.64 developed an alkyne metathesis reaction to synthesize a 2D GY-like porous carbon-rich network. The high catalytic reactivity of this synthesis method significantly reduces reaction time, effectively minimizing oxidation and aggregation. In order to synthesize a GY-like porous carbon-rich network, 1,3,5-tripropynylbenzene was utilised as the precursor, which underwent polymerization catalyzed by tris(t-butoxy)(2,2-dimethylpropylidyne)tungsten(VI) at 80 °C for 24 h under an argon atmosphere, without stirring. Beyond these synthetic strategies, hydrogen substitution has been explored as a means to further modulate GY properties. Although less frequently studied, hydrogen substitution provides a way to fine-tune the structural and electronic properties without substantially altering its conjugated network. This subtle modification can improve the material's stability, electronic tunability, and interaction with surrounding molecules, making HsGY a topic of growing interest. Theoretical studies suggest that GY is a promising candidate for the oxygen evolution reaction (OER) owing to its high charge carrier mobility.65
In a significant advancement, mechanochemical ball milling has been proposed as a low-cost and scalable approach to induce carbon–carbon bond rearrangements and generate GY-like structures without the need for metal catalysts or high-temperature processing. However, the structural nature of the materials produced via this method remains a subject of active debate. Early work by Li et al.66 achieved the synthesis of a six-fold symmetric γ-GY spoked wheel (see Fig. 3) by employing a triyne intermediate (DBA f) and executing a 12-fold intramolecular Stille coupling reaction.
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| Fig. 3 Synthesis of γ-GY by the mechanochemistry method.66 | ||
Cui et al.67 later synthesized HsGY via a ball milling method, utilizing tribromobenzene (C6H3Br3) and CaC2 as precursors. By substituting C6H3Br3 with hexabromobenzene (C6Br6), GY was subsequently synthesized using the same ball milling approach.66 Subsequent mechanochemical advances enabled gram-scale γ-GY production, notably through the conversion of benzene using calcium carbide (CaC2) under ball-milling conditions, as depicted in Fig. 4, highlighting the scalability and cost-effectiveness of this approach.68,69 Nevertheless, structural analyses consistently indicate that such products exhibit limited crystalline coherence and high defect densities. Li et al.70 synthesized HsGY films at the gas–liquid interface via an alkyne metathesis reaction using 1,3,5-tripynylbenzene (TPB) as the precursor. The resulting HsGY film exhibits a layered structure and is suitable as a sulfur host matrix for lithium–sulfur batteries (LSBs), owing to its extended π-conjugated carbon framework composed of acetylenic linkages and benzene rings. Song et al.71 introduced an innovative and facile liquid/liquid interfacial synthesis strategy as a general approach for the preparation of GY analogs. This approach enabled the fabrication of various substituted GY analogs, including hydrogen-substituted (H-GY), methyl-substituted (Me-GY), and fluorine-substituted (F-GY) variants. These materials feature a unique structural motif, characterized by a single acetylenic linkage between adjacent benzene rings, resulting in distinct pore architectures and electronic properties. The synthesized GY analogs formed continuous, large-area films with well-organized, gauze-like membrane structures observable at the micrometer scale. The electrical conductivities of H-GY, Me-GY, and F-GY were measured at 0.041 S m−1, 0.076 S m−1, and 0.028 S m−1, respectively, highlighting the effect of functional substitution on their electronic performance. Yang et al.72 prepared porous HsGY via liquid–liquid interfacial polymerization. Although considerable progress has been made in the study of GYs, their synthesis remains a significant challenge, primarily due to the difficulty in constructing acetylenic (C
C) linkages.
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| Fig. 4 Synthesis of γ-GY by the modified mechanochemical method with benzene and CaC2 as precursors.68 | ||
In 2020, Lin et al.73 further employed a modified mechanochemical route to synthesize γ-GY for photocatalytic applications, demonstrating functional utility but without resolving intrinsic disorder or establishing extended periodicity. Ding et al.74 successfully produced γ-GY by using CaC2 and hexabromobenzene (PhBr6) as reactants through the sonochemical method. Atomically precise fabrication of well-defined nanostructures is possible using on-surface synthesis methods. Sedona et al.75 reported the on-surface synthesis of extended linear GY molecular wires (GY MWs) through an Ullmann-type aryl halide homocoupling reaction. To circumvent the challenges associated with highly reactive terminal alkynes, the authors employed 1,2-bis(4-bromophenyl)ethyne (DBPE) as a molecular precursor. In this design, the acetylenic group is positioned internally, linked by two phenyl rings, each functionalized with a bromine atom at the para position. This configuration facilitates controlled linear homocoupling, leading to the formation of long GY MWs arranged in dense, ordered arrays. Moreover, Yu et al.76 fabricated GY MWs through on-surface synthesis with stepwise reactions.
Nitrogen (N)-doped GY incorporates nitrogen atoms into the carbon framework, introducing charge delocalization, modifying the electronic band structure, and creating chemically active sites. These changes significantly enhance the performance of GY in applications such as electrocatalysis, sensing, and energy storage. Ding et al.77 reported a one-step ball-milling approach for the first facile synthesis of nitrogen-doped GY (N-GY) with controllable doping sites. By employing CaC2 and pyrazine as reactants, nitrogen atoms were precisely incorporated into the γ-GY framework, leveraging pyrazine as both a nitrogen source and structural modifier. The resulting material showed an average yield of one gram. In a study by Abdi et al.,78 a nitrogen-doped GY analogue called triethynylbenzene coupled with cyanuric chloride (TCC) was synthesized through a solvothermal (Sonogashira cross-coupling) reaction between 1,3,5-triethynylbenzene (1,3,5-TEB) and cyanuric chloride in an equimolar ratio. This approach enabled the formation of a conjugated network incorporating triazine moieties, introducing a nitrogen functionality into the carbon framework.
To overcome the challenges associated with constructing acetylenic (C
C) linkages, recently one research group of Liang et al.79 designed a novel precursor, 1,3,5-tris(tribromomethyl)benzene (tTBP), bearing tribromomethyl functional groups and successfully transformed this compound into a C
C triple-bonded structural motif through on-surface dehalogenative homocoupling reactions conducted under ultrahigh-vacuum conditions. Drop-coating technique was employed by Gao et al.80 to produce γ-GY/TiO2 nanotube (GY/TNT) heterostructures. In a significant advancement in carbon allotrope research, Pan et al.81 reported the direct bottom-up synthesis of crystalline GTTY using hexa(buta-1,3-diyn-1-yl)benzene as a precursor. The resulting GTTY exhibited a 2D lamellar architecture with uniform 0.9 nm pores, 80% sp-hybridized carbon atoms, a direct band gap of 1.3 eV, an electrical conductivity of 0.285 S m−1 at room temperature, and outstanding charge carrier mobilities of 1.47 × 103 cm2 V−1 s−1 (holes) and 2.98 × 103 cm2 V−1 s−1 (electrons).
Another study reported the synthesis of γ-GY via reversible dynamic alkyne metathesis reaction of alkynyl-substituted benzene monomers, which is depicted in Fig. 5. This work focused on reaction feasibility.82 More recently, Yang et al.83 have optimized mechanochemical parameters to enhance the dye adsorption performance, again confirming that localized acetylenic linkages can be introduced efficiently, yet long-range ordered γ-GY lattices remain elusive. However, growing evidence suggests that mechanochemical routes predominantly yield disordered or semi-ordered carbon frameworks with localized acetylenic linkages, rather than long-range ordered GY lattices.
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| Fig. 5 Bulk synthesis of γ-GY through alkyl metathesis82 using monomers 1,2,3,4,5,6-hexapropynylbenzene (HPB) and 1,2,3,4,5,6-hexakis [2-(4-hexylphenyl)ethynyl] benzene (HHEB). | ||
Barua et al.84 synthesized γ-GY via a one-pot Sonogashira cross-coupling reaction, employing PhBr6 and CaC2 as the primary reactants, and obtained an overall product recovery of approximately 80%, as shown in Fig. 6.
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| Fig. 6 One-pot Sonogashira cross-coupling reaction for synthesizing γ-GY.84 | ||
The synthesis of bulk γ-GY has long posed a significant challenge due to its complex structure and stability requirements. Desyatkin et al.85 reported a breakthrough in this area by demonstrating the scalable synthesis of multilayer γ-GY via crystallization-assisted irreversible cross-coupling polymerization. This method enabled the formation of well-defined multilayer γ-GY crystals with structural integrity and uniformity, marking a major step toward the practical realization and exploration of this elusive carbon allotrope. Nitrogen-doped GY compounds (NGY-1 and NGY-2) were synthesized via the Sonogashira–Hagihara cross-coupling reaction, employing hydrogen-deficient multi-acetylene and polyhalogenated monomers as co-monomers.86 The development of hybrid materials such as GY-based nanocomposites that integrate GY with metals, metal oxides, polymers, or other nanostructured materials has opened new possibilities for multifunctional materials. These composites leverage the intrinsic properties of GY while enhancing the mechanical strength, chemical functionality, and application-specific performance, particularly in catalysis, energy conversion, environmental remediation, and nanodevices. Via an in situ sonochemical process, Zheng et al.87 prepared BiOBr nanocomposites with nitrogen doping on GY. Liu et al.88 used a Castro–Stephens-type coupling reaction to synthesize ultrathin single-crystalline HGY with a new monomer called 1,3,5-tribromo-2,4,6-triethynylbenzene (see Fig. 7). The newly developed HGY was constructed by alternately linking sp2-hybridized benzene rings with sp-hybridized C
C bonds. It features large intrinsic pores with diameters in the range of approximately 0.8–1.0 nm.
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| Fig. 7 Synthesis of ultrathin, single, crystalline HGY via the Castro–Stephens-type coupling reaction.88 | ||
Liu et al.89 used a mechanochemical ball-milling strategy to construct GDY-based Ni-doped MoS2 heterojunctions for photocatalytic hydrogen evolution. Here, mechanochemistry primarily enabled composite formation and interfacial charge-transfer engineering, with GDY embedded in a multiphase system rather than formed as a long-range crystalline network, highlighting the limitation of this approach for achieving ordered sp–sp2 carbon lattices. The highly energetic and random nature of ball milling induces bond breaking and defect formation, which hinders the controlled assembly of long-range ordered sp–sp2 carbon networks needed for true GY crystals. Wu and co-workers90 produced titanium dioxide (TiO2)/γ-GY nanocomposites. The controlled synthesis of GYs with specific topologies and desirable functional properties remains a major concern. To address this, He et al.91 introduced a novel one-pot approach for the synthesis of γ-GY via a palladium (Pd)-catalyzed decarboxylative coupling reaction between hexabromobenzene and acetylenedicarboxylic acid (see Fig. 8). This method, conducted under mild conditions, offers a significant improvement over conventional techniques such as mechanical ball milling or ultrasonic-assisted synthesis. Notably, it enables the production of γ-GY with high yields and low equipment demands, making it a promising strategy for scalable and cost-effective manufacturing. Additionally, the resulting γ-GY-supported Pd nanoparticles exhibited high catalytic activity, further highlighting the practical potential of this approach.
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| Fig. 8 One-pot synthesis of γ-GY.91 | ||
Zhang et al.92 fabricated a GRA/γ-GY heterostructure via a mechanosynthesis route, and the obtained material showed enhanced electromagnetic wave absorption across gigahertz and terahertz ranges. Moreover, this study demonstrates the strength of combining high-conductivity GRA with sp–sp2 hybridized γ-GY to improve dielectric loss and impedance matching, leveraging the long-range order and crystallinity of both materials. While the approach is scalable and cost-effective, the reliance on pre-synthesized components and precise assembly limits uniformity over large areas, and interfacial defects may reduce reproducibility and long-term stability. Yin et al.93 employed a dehalogenative homocoupling reaction to synthesize hydrogen-substituted graphdiyne (HsGDY) in a powder form, providing a relatively simple, eco-friendly, and moderately scalable method. The work highlights the importance of hydrogen substitution in tuning the electronic properties and maintaining sp–sp2 conjugation. While the method is mild and cost-effective, precise control over hydrogen content and achieving uniformity across bulk samples remain challenges, potentially affecting the consistency of electronic performance in devices. Jin and Wu94 introduced a green, high-yield preparation method for GDY and HsGDY using sustainable precursors under environmentally benign conditions. The method successfully balances scalability, cost-effectiveness, and environmental considerations. Although precise control over long-range structural order and domain size remains a challenge, their materials demonstrated efficient visible-light photocatalytic activity due to enhanced charge separation. However, the work also reveals the limitations: defect density and surface functionalization are critical factors, and uncontrolled defects can degrade photocatalytic stability, limiting practical application.
Rapid gram-scale synthesis of γ-GY and its functional derivatives using a straightforward metal-free wet-chemical method (see Fig. 9) was introduced by Song et al.95 This approach relies on nucleophilic aromatic substitution reactions between fluoro-(hetero)arenes and alkynyl silanes, facilitated by catalytic TBAF. The fluoride ions effectively remove protecting groups from the alkynyl silanes, generating reactive alkynylide species that drive crosslinking. This versatile method tolerates a wide range of functional groups and enables the synthesis of diverse fluorine (F) and N-enriched γ-GY derivatives using electron-deficient fluoro-substituted (hetero)arenes as starting materials. The metal-free wet-chemical method offers a scalable and cost-efficient process inspiring the development of novel carbon-based materials.
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| Fig. 9 Gram-scale fast synthesis of γ-GY using a metal-free wet chemistry method.95 Reaction pathway represents the preparation of γ-GY from 1,3,5-trifluoro-2,4,6-tris[2-(trimethylsilyl)ethynyl]-benzene (TFTEB). | ||
Huang et al.96 successfully fabricated ternary N-GY-Bi2S3/BiOBr composites via an in situ ultrasound-assisted method. In another study, Zhao et al.97 reported the synthesis of nitrogen-doped GY/g-C3N4 (NGY/CN) composites via an in situ sonochemical method. For the effective removal of levofloxacin, Li et al.98 developed flower-like N-GY/bismuth oxyhalide (BiOCl0.5Br0.5) microspheres via a simple, one-step sonochemical method. The incorporation of N-GY significantly improved both the adsorption capacity and the photocatalytic degradation efficiency under visible light, surpassing the performance of pristine BiOCl0.5Br0.5. This study also demonstrates the promising application of N-GY-based composites in advanced photocatalytic water purification. In an innovative approach combining environmental remediation and materials synthesis, Li et al.99 suggested a green method for producing oxygen-doped GY through the mechanochemical degradation of decabromodiphenyl ether (BDE-209), a hazardous brominated flame retardant. The synthesized material demonstrated excellent electrical conductivity and a high specific capacitance of 257.6 F cm−3, making it a strong candidate for electrochemical energy storage. This work not only presents a sustainable pathway for GY synthesis but also offers a practical solution for the disposal of persistent organic pollutants. Huang et al.100 hydrothermally synthesized porous N-GY/TiO2/Ti3C2 heterostructures with strong interfacial coupling and later101 produced ternary x-N-GY/Bi/BiOBr composites via solvothermal synthesis, promoting efficient charge separation and superior photocatalytic activity.
Lee et al.102 reported the fabrication of heteroatom-doped (F-doped) GY. Planetary milling was carried out to enhance the structural and electrochemical properties of GY. This approach facilitated the formation of fine particles and increased the content of alkynyl carbon, thereby promoting a higher density of electrochemically active sites and improving both electrical and ionic conductivity. Fluorine, possessing the highest electronegativity (3.98), introduces significant polarity and dipole moments into the GY framework upon doping. As a result, F-doping contributes to improved electrical conductivity and supports superior ultrafast cycling stability. The combined effects of alkynyl carbon and F doping in the GY structure suggest that F-doped GY holds strong potential as an active material for high-performance electrical double-layer capacitors (EDLCs). Krøll et al.103 explored the stepwise synthesis of tetraethynylethene (TEE) scaffolds as molecular models for segments of 6,6,12-GY, an all-carbon network composed of interspersed sp-and sp2-hybridized carbons within a GRA-like lattice. Utilizing a series of Sonogashira coupling reactions, the authors constructed various TEE derivatives starting from vinylic dibromide precursors and phenylacetylene. Through carefully controlled protodesilylation and cross-coupling steps, they obtained mono-, di-, and trimeric TEE structures with different arylation patterns, including fully substituted and linearly conjugated trimers. The synthesized TEE scaffolds exhibited excellent solubility in chlorinated solvents, providing well-defined model compounds for investigating the properties of 6,6,12-GY.
Shu et al.104 reported F-functionalized GY decorated with transition metals for CO2 electroreduction, where surface fluorination allowed the precise control of hydrophobicity and adsorption sites, yielding a material with high surface area, uniform active centers, and long-range structural order. The method is cost-effective, eco-friendly, and scalable, offering improved catalytic efficiency, though large-scale electrode fabrication and long-term stability remain challenges. Chen et al.105 explored the effect of calcination temperature on γ-GY for simultaneous electrochemical detection of dopamine, uric acid, and ascorbic acid. Their thermal treatment approach fine-tuned the material's porosity, conductivity, and crystallinity, resulting in enhanced sensitivity and selectivity. While energy-efficient and scalable, precise temperature control is critical to reproducibility. Min et al.106 fabricated γ-GY/graphitic carbon nitride quantum dot (CNQD) hybrids by a facile solution-based self-assembly method, improving the tribological performance of epoxy composites via strong interfacial interactions and uniform dispersion. The process is environmentally friendly and cost-effective, though uniform large-scale incorporation of quantum dots may be a challenge. Tian et al.107 developed N-doped γ-GY coupled with Ti3+-doped TiO2 using hydrothermal-assisted in situ growth for photocatalytic green ammonia synthesis. The heterostructure exhibited enhanced visible-light absorption, charge separation, and abundant active sites, providing high efficiency with good crystallinity and structural order, though long-term stability under illumination remains a concern. Zhang et al.108 synthesized highly dispersed cerium dioxide (CeO2) nanocubes on HsGY sheets for room-temperature NH3 sensing. The hydrothermal growth method ensured uniform nanocube distribution and excellent crystallinity, resulting in high sensitivity, selectivity, and humidity-independent performance, while precise nanocube size control is critical for consistent sensor functionality. The recent experimental and theoretical developments in GBM synthesis are presented in Tables 1 and 2.
| Synthesis method | Graphyne-based material | Developments and limitations | Ref. |
|---|---|---|---|
| Gas–liquid interface via alkyne metathesis | HsGY films | Interface-confined growth enables film formation but crystallinity control remains limited; energy storage (Li–S batteries); high reversible capacity and cycling stability | 70 |
| Liquid–liquid interfacial synthesis | GY analogs | Continuous large-area films; gauze-like membranes; structures are polycrystalline with limited long-range order | 71 |
| Liquid–liquid interfacial polymerization | Porous HsGY | Good crystallinity; area up to 33 cm2; high Na-ion storage performance; scalability, but synthesis complexity is high | 72 |
| Solid–liquid interface via mechanosynthesis | γ-GY | Direct benzene-to-γ-GY conversion; gram-scale; low environmental impact; scalable; long-range crystalline order over large areas remains elusive due to mechanochemical disorder | 68 |
| Stepwise on-surface approach | GY nanowires | Atomically precise nanowires; limited to surfaces and small areas; not scalable | 76 |
| On-surface Ullmann-like aryl halide homocoupling | Gy MWs | Long, linear, ordered molecular wires; requires UHV/metal substrates; limiting practicality | 75 |
| Modified mechanochemical method | γ-GY | GY-like frameworks with high defect density rather than ideal crystals; γ-GY as an electron transfer layer | 73 |
| Ultrasound-promoted method | γ-GY | Method is nontoxic, low cost, easy to be industrialized; high yield; structural heterogeneity persists; solar energy applications | 74 |
| Mechanochemical ball-milling | N-doped GY | Tunable N sites; effective for doping and functionalization but induces defects and amorphization | 77 |
| Sonogashira cross-coupling | N-GY | Controlled chemical bonding; limited film size and scalability | 78 |
| Dehalogenative homocoupling | HsGY | Short reaction time; large-scale industrial synthesis; metal-free advantage; crystallinity still moderate | 79 |
| Drop-coating method | γ-GY/TiO2 nanotube array heterostructures | Environmentally friendly; GY acts as functional coating rather than standalone crystal; photoelectrochemical and photoelectrocatalytic application | 80 |
| Glaser–Hay coupling | GTTY | Highly ordered crystalline GTTY-average thickness of 4.5 nm; 80% sp-carbon content; precisely controlled and well-defined chemical structure | 81 |
| Modified mechanochemical method | γ-GY | Simple, efficient; prioritizes scalability over crystallinity | 83 |
| One-pot Sonogashira cross-linking | Pristine γ-GY | High yield, CaC2 as the acetylene source; claims pure, defect-free structure under mild conditions; large-area crystallinity not established; energy storage, electronic, and optoelectronic applications | 84 |
| Sonogashira–Hagihara cross-coupling | N-doped GY | Copolymerization-based direct organic synthesis; high supercapacitor performance with excellent cycling properties; construction of functional heteroatoms-doped GY; strong chemical control; moderate scale | 86 |
| In situ sonochemical synthesis | N-doped GY/BiOBr composite | Composite-focused rather than intrinsic GY order; excellent photocatalysis | 87 |
| Castro–Stephens-type coupling | HGY | First, ultrathin, single-crystalline HGY; high structural precision but low throughput; applications in optoelectronic and energy-related fields | 88 |
| Crystallization-assisted irreversible cross-coupling polymerization | γ-GY | Scalable multilayer γ-GY; aperiodic sheet stacking; thermally stable up to 240 °C, transforms at higher temperatures; ordered covalent lattice formed under kinetic control | 85 |
| Mechanochemical | GRA/γ-GY heterostructure | Functional performance prioritized over structural perfection; as electromagnetic wave (EMW) absorber | 92 |
| Dehalogenative homocoupling | HsGDY | Pd catalyst-free; short reaction time; scalable; improved practicality with moderate order; application in electrochemical catalysis | 93 |
| One-pot method | Few layer γ-GY | Easy to perform with mild reaction conditions, low-cost, high yield with low equipment requirements; outperforms ball milling or ultrasonic synthesis in yield but not crystallinity; application in catalysis | 91 |
| Hot-solvent method | GDY and HsGDY | Low cost; high yield; safer than traditional cross-coupling methods and mechanical routes; limited structural order; application in photocatalysis | 94 |
| Metal-free nucleophilic crosslinking method | GY and its derivatives | Fast, gram-scale synthesis; metal-free; scalable; cost-effective approach; reduced synthetic barriers for GY derivatives; functional group tolerance; significant step toward industrial feasibility; applications in catalysis | 95 |
| Hydrothermal method | Porous N-GY/TiO2/Ti3C2 composites | First construction of porous N-GY/TiO2/Ti3C2 composites; GY acts as active component in hybrids; superior photocatalytic activity | 100 |
| In situ sonochemical synthesis | N-doped GY/porous g-C3N4 composites | CaC2-based synthesis; composite limits structural assessment; applications in photocatalysis | 97 |
| In situ sonochemical synthesis | N-GY/BiOCl0.5–Br0.5 microsphere | Functional integration emphasized; applications in photocatalysis | 98 |
| Solvothermal method | N-GY-Bi/BiOBr composites | 3D microspheres; hierarchical architecture over crystallinity; applications in photocatalysis | 101 |
| In situ ultrasound-assisted synthesis | N-GY–GY/Bi2S3/BiOBr composites | First synthesis; superior photocatalytic activity; multi-phase complexity; applications in photocatalysis | 96 |
| Mechanochemical | Oxygenic GY | Green synthesis; hazardous decabromodiphenyl ether converted into oxygenic GY; highly ordered multilayered structure; electrode for supercapacitors; high electrochemical performance; excellent cycling stability | 99 |
| Planetary milling | F-doped GY | Excellent EDLCs performance; cycling stability; high doping efficiency, lattice order uncertain | 102 |
| Stepwise–Sonogashira couplings | 6,6,12-GY | TEE scaffolds-molecular models of 6,6,12-GY segments | 103 |
| Aromatic nucleophilic substitution strategy | Fluorographynes | Tunable fluorine content enables wettability control; novel strategy for catalysts with tunable hydrophobic microenvironments; chemical versatility over crystallinity | 104 |
| Ultrasonic sonochemical method | Calcined γ-GY | Electrochemical sensing; structural disorder acceptable for sensing | 105 |
| Hydrothermal method | γ-GY/graphitic (CNQDs) hybrids | Advanced materials; hybrid functionality focus; aerospace applications | 106 |
| Mechanochemical | N-doped γ-GY/Ti3+-doped TiO2 | Prepared for photocatalytic nitrogen fixation and enhanced photocatalytic activities; interface engineering dominates | 107 |
| Hydrothermal method | CeO2/HsGY | GY as conductive scaffold; humidity-independent NH3 sensing | 108 |
| Material | Method | Theoretical advancement | Ref. |
|---|---|---|---|
| Oxygenated GY | DFT | Predicted tunable electronic band structure upon oxygen coverage; zero-gap to semiconducting transition via functionalization | 109 |
| α,β,γ-GY | DFT | First systematic first-principles evaluation of structural, elastic, electronic properties including band structures, Fermi velocity, strain effects | 110 |
| cp-GY (carbon pentagons + acetylenic links) | DFT | Novel low-energy GY polymorph; distorted/anisotropic Dirac cones and semimetallic nature-new electronic possibilities | 111 |
| Doped/heteroatom GY/GDY | DFT | Predicted mechanical, optical and electronic properties of GY with B, N, P, Al dopants; tunable band features | 112 |
| PG-yne | DFT | Energetically more favorable than other GY family members, including experimentally synthesized GY and GDY; dynamically, thermally, and mechanically stable up to 1000 K; high carrier mobility with excellent optical properties; promising for future electronic and optoelectronic applications | 113 |
| D GY-like covalent triazine framework (GYCTF) | Dispersion-corrected DFT | Functionalized GY-like frameworks; Mg-ion adsorption and surface interactions on GY derivatives for battery applications | 114 |
| Nonconventional α-GY nanocarbon | DFT | Proposal of nonconventional GY lattices inspired by sp2 nanocarbon haeckelites; systematic mapping of the structural and electronic properties of modified α-GY nanocarbons | 115 |
| PG-yne | Atomistic reactive MD simulations | Mechanical properties and fracture behavior of PG-yne monolayers and nanotubes; structural topology strongly influences elastic constants; PG-yne systems-extended, topology-independent plastic deformation region prior to fracture | 116 |
| R-GY | DFT | Theoretical HER/OER activity predicted for novel R-GY; demonstrating GY's catalytic potential | 117 |
| α-2 GY based catalysts | DFT + machine learning (ML) | Large-scale DFT screening, integrated with machine learning, identifies stable dual-atom catalysts on graphyne, highlighting TM–TM DACs as a promising catalyst class with high electroactivity and long-term durability | 118 |
| γ-GY | Density functional tight binding method within the DFTBEPHY framework | Advanced modeling of electron–phonon coupling and charge transport in semiconducting GYs; GYs exhibit GRA-like electronic properties with intrinsic band gaps; phonon-limited mobilities lie between GRA and MoS2 for GY and are comparable to MoS2 for GDY | 119 |
| TH-GY | DFT, AIMD, and classical reactive MD simulations | Novel 2D allotrope that combines triangular (T) and hexagonal (H) rings, connected by acetylenic linkages; AIMD and phonon analyses confirm thermal and dynamical stability; band structure calculations reveal metallic behavior and a Young's modulus of 263–356 GPa | 120 |
Despite notable progress in GBM synthesis, the realization of large-area, highly crystalline, and defect-controlled materials remains limited, reflecting fundamental challenges that have persisted since the theoretical proposal of GY in the mid-1990s, including the thermodynamic instability of acetylenic linkages and the lack of efficient error-correction during growth. Early efforts through the 2000s and 2010s were largely limited to theoretical studies and molecular or oligomeric fragments, with GDY emerging as a more accessible analogue but without achieving long-range crystalline GY. From the late 2010s onward, multiple synthesis strategies have been explored, each involving intrinsic trade-offs between crystallinity, scalability, and process complexity. On-surface synthesis under ultra-high vacuum provides unparalleled atomic-level precision and well-defined acetylenic coupling, serving as a critical proof of concept, yet its stringent vacuum conditions, substrate dependence, low throughput, and sub-millimeter growth areas fundamentally preclude scalable production. CVD, despite being the most scalable approach for 2D materials, has thus far failed to yield highly crystalline GY, as high growth temperatures promote competing sp2 carbon formation, bond rearrangements, and irreversible defect accumulation, resulting in polycrystalline or amorphous GY-like films with limited domain sizes. In contrast, solution-based, mechanochemical, and ultrasonic-assisted routes developed after 2020 enable gram-scale production of γ-GY and related derivatives under comparatively mild, cost-effective, and in some cases, metal-free conditions, making them attractive for large-scale processing; however, limited reaction control leads to high defect densities, incomplete acetylenic coupling, stacking disorder, and poor long-range order, causing material properties to fall well below theoretical expectations.
A notable advance in the 2022–2025 period is the emergence of crystallization-assisted irreversible cross-coupling polymerization. This approach enables bulk solution polymerization of multilayer γ-GY, where a crystallization step promotes long-range ordering and network growth beyond surface-confined domains. Unlike conventional Sonogashira or Glaser coupling methods, which often yield small fragments or require stringent surface control, this strategy (i) operates in bulk solutions and is therefore scalable, (ii) forms extended covalent networks rather than isolated oligomers, and (iii) yields significantly larger material quantities.
As a result, it offers the best balance between structural quality and scale-up potential. A very recent development reports a metal-free nucleophilic wet-chemistry route that produces γ-GY derivatives at gram scale under mild conditions. Gram-scale production at bench level is an important milestone: it demonstrates that reagents and reaction conditions can be adapted to produce larger batches without transition-metal catalysts (i.e., reducing cost and contamination issues). This metal-free wet route thus represents a highly practical path to scale because it simplifies reagents and reactor conditions. Overall, no single method yet satisfies the combined requirements of large-area growth, high crystallinity, low defect density, scalability, cost-effectiveness, and environmental benignity: on-surface synthesis excels in structural precision, CVD in scalability, and mechanochemical routes in cost and throughput, but each suffers fundamental limitations. As of 2025, crystallization-assisted and metal-free wet-chemical strategies represent the most promising pathways toward practical GBMs, provided that future efforts prioritize defect-aware growth, precursor design, and rigorous structure–property correlations. In this context, theoretical advancements play a critical complementary role. Table 2 summarizes the recent progress in DFT and the advanced simulation approaches that elucidate structure–property relationships and thus guide experimental efforts. These studies offer predictive insights into thermodynamic stability, preferred bonding motifs, and feasible lattice topologies, enabling rational selection of precursors, functional groups, and synthesis conditions. Furthermore, theoretical screening of functionalization, doping, and lattice engineering strategies identifies promising GY allotropes with targeted electronic, mechanical, and catalytic properties prior to experimental realization, thereby reducing trial-and-error synthesis and accelerating the development of scalable, application-ready GBMs.
Despite having half the density of GRA, it retains comparable interfacial adhesion and out-of-plane deformation to GRA. Key elastic properties including in-plane rigidity and Poisson's ratio influence its mechanical behavior. Poisson's ratio of GYs is 0.429, which is twice that of GRA. Moreover, the value approaches that of a perfectly incompressible material (0.5). Thus, GY demonstrates high structural preservation under tensile stress.123 Theoretical studies indicate that γ-GY has a lower in-plane strength than that of GRA (i.e., 170–240 N m−1) but remains the most stable under shear stress.124,127 Poisson's ratio exhibits a steady decrease from γ-GY to α-GY, indicating that γ-GY demonstrates the highest structural stability under shear stress, whereas α-GY shows lower stability.124 The fracture limit of the γ-GY network is path-dependent, as revealed by uniaxial tensile tests. Young's modulus was determined to be 532.5 GPa in the armchair direction and 700.0 GPa in the zigzag direction, highlighting its anisotropic mechanical behavior. The ultimate tensile strength of GY-n is predicted to follow a linear scaling relationship, being directly proportional to the number of atomic linkages within the structure. Fracture analysis indicates that crack initiation predominantly occurs at weaker single bonds within the acetylenic linkages, ultimately leading to the catastrophic failure of the entire sheet.125 In-plane stiffness and Poisson's ratio are key elastic parameters used to characterize the mechanical behavior of GBMs. Studies have shown that these materials typically exhibit lower in-plane stiffness than GRA.123,128 Furthermore, their Poisson's ratios, ranging from 0.39 to 0.87, are notably higher than that of GRA.129
Ajori et al.130 examined the impact of vacancy defects on the mechanical properties of GY, specifically strain, stress, Young's modulus, and Poisson's ratio, through MD simulations utilizing the Tersoff–Brenner potential. Their study revealed that GY exhibits reduced mechanical strength and stiffness in comparison to GRA, highlighting the influence of structural defects on its overall mechanical performance. Nonetheless, research by Shao et al.131 and Zhang et al.132 suggests that the mechanical properties of GBMs may vary with temperature. Although these initial studies offer important observations, further investigation is needed in this area to fully understand and characterize the temperature-dependent behavior of GBMs. Wu et al.133 conducted MD simulations with the adaptive intermolecular reactive empirical bond order (AIREBO) potential to assess the fracture stress, fracture strain, and stiffness of GY structures under armchair and zigzag loading conditions. Their results demonstrated that the number of acetylenic chains connecting the hexagonal rings strongly depends on the mechanical properties of GBMs. Recently, Xiao et al.134 have experimentally investigated the mechanical properties of GDY films for the first time using atomic force microscopy (AFM) nanoindentation techniques. The measured three-dimensional elastic modulus ranged from 145.6 to 273.6 GPa, with an average value of 218.5 GPa. This experimentally determined elastic modulus is notably lower than the ideal theoretical value, which can be attributed to the presence of structural defects and the finite thickness of the synthesized GDY films. Previous studies have shown that the elastic modulus of carbon nanostructures decreases significantly with the increase in vacancy.135 In addition, Xiao et al.134 reported a pronounced reduction in elastic modulus with the increase in layer number in GDY films, further highlighting the strong influence of thickness and structural imperfections on their mechanical performance. GY exhibits notable impact resistance and distinctive elastic wave propagation behavior, indicating strong structural robustness for protective nanomaterial applications.136 The elastic properties of γ-GY are highly sensitive to nanoscale dimensions, an important consideration for the design of nano-mechanical devices.137 Mechanical anisotropy and deformation behavior have been shown to depend strongly on atomic configuration and bonding topology.138 Combined DFT and continuum modeling approaches have been employed to evaluate the stiffness and compliance constants across different GY allotropes, revealing pronounced variations in elastic constants with the type of structure.139 Recent studies have emphasized fundamental mechanical parameters such as breaking strength and failure strain derived from stress–strain responses, underscoring the suitability of GY for flexible nanoelectronic applications.140 Furthermore, MD simulations have elucidated the effects of wrinkling, fracture mechanisms, and anisotropic tensile loading in various GY configurations, providing deeper insights into mechanical failure processes.141 Across all reviewed studies, the mechanical parameters consistently demonstrate that GBMs possess robust mechanical stability, reinforcing their potential as promising candidates for membrane-related applications.
| Properties | Ultimate strength, σ (N m−1) | Ultimate strain, ε (%) | In-plane stiffness, C (N m−1) | Poisson's ratio, ν | Hole, µh (×104 cm2 V−1 s−1) | Electron mobility, µe (×104 cm2 V−1 s−1) | Ref. | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Direction | σ x | σ y | ε x | ε y | C x | C y | ν x | ν y | µ hx | µ hy | µ ex | µ ey | |
| GY | 17.84, 16.68, 14.34, 14.44 | 18.83, 21.16, 31.97, 20.47 | 20, 11.2, 8.19, 11.2 | 20, 14.8, 13.24, 17.7 | 166, 170.4, 166.3, 162.1, 150, 170.2, 164, 163 | 224.0, 169.2, 162.5, 159.6 | 0.417, 0.416, 0.429, 0.42, 0.39 | 0.42, 0.38 | — | — | — | — | 123–126, 128 and 172–174 |
| GDY | 10.71, 9.54 | 13.54, 20.84 | 6.3, 10.9 | 8.0, 20.8 | 123.1, 150.2, 100, 118.6, 121.8 | 185.2, 117.5 | 0.446, 0.40, 0.453 | 0.40 | 1.91 | 1.97 | 17.22 | 20.81 | 48, 126, 172 and 174–176 |
| α-GY | 10.88 | 12.18 | 15.6 | 17.8 | 39.9, 24, 21.98, 22.48, 42.8 | 40.2, 42.4 | 0.863, 0.87, 0.874, 0.72 | 0.72 | 2.960 | 3.316 | 2.716 | 3.327 | 110, 125, 174 and 176–178 |
| β-GY | 12.75 | 15.50 | 13.0 | 16.2 | 87.1, 83.77, 73.07, 93.6 | 87.4, 92.1 | 0.49, 0.647, 0.67, 0.52 | 0.51 | 0.856 | 1.076 | 0.798 | 0.892 | 110, 125, 174, 176, 177 and 179 |
| 6,6,12-GY | 13.09, 34.71, 30.15 | 20.64, 41.94, 35.85 | 11.6, 0.134, 0.13 | 14.7, 0.191, 0.2 | 117.3, 121.1, 347, 348, 333, 341.09 | 149.1, 152.1 | 0.39, 0.164, 0.169, 0.18 | 0.49 | 12.29 | 42.92 | 24.48 | 54.10 | 110, 125, 172, 174, 176, 180 and 181 |
Interestingly, the study found that the thermal conductance remained largely unaffected by the presence of acetylenic linkages. The thermal characteristics of 2D materials are influenced by interatomic spacing, leading to reduced thermal conductivity at higher temperatures.149 The lower molecular density and weaker single carbon bonds in the acetylene link contribute to a significant reduction in GY's thermal conductivity.
Notably, the thermal conductivity of GY is primarily determined by the number of aromatic rings rather than the presence of alkyne bonds. Additionally, both temperature and external strain influence the thermal sensitivity of GY structures. Hu et al.150 reported that pristine γ-GY nanotubes possess exceptionally low thermal conductivity, substantially lower than that observed in typical, defect-laden, or chemically modified carbon nanotubes (CNTs). Zhang et al.151 examined the thermal conductivity of δ-GY and found that it consistently decreased with the increase in temperature, a behavior attributed to the influence of acetylenic linkages within the structure. This observation, along with similar findings from previous studies, highlights the inherent challenge of heat transport in GBMs, which stems from their characteristically low thermal conductivity. The minimal thermal efficiency of α-GY, β-GY, and γ-GY are 0.920, 1.650, and 2.456, respectively.152
An additional area of growing interest is the thermoelectric performance of GBMs. Environmentally safe thermoelectric materials enable direct conversion between heat and electricity, with GY exhibiting superior thermoelectric characteristics compared to GRA. Despite their relatively low thermal conductivity compared to GRA, GBMs have demonstrated promising thermoelectric behavior in theoretical studies. The inherent band gaps in their electronic structures are key contributors to enhanced Seebeck coefficients, leading to a potentially high thermoelectric figure of merit. These characteristics make GBMs attractive candidates for next-generation thermoelectric materials, as supported by the findings previously reported in the literature.145,146,153 Typically, an ideal thermoelectric material is expected to exhibit a dimensionless figure of merit (ZT) greater than 3. In a study by Sun et al.,153ZT values of 3 and 4.8 were reported for p-type holes and n-type electrons, respectively, in GBMs at 293 K. These results were obtained by integrating MD and first-principles simulations with the Boltzmann transport theory. Such high ZT values highlight the strong potential of GBMs as promising candidates for high-performance thermoelectric applications. Studies on GRA/GY heterostructures showed that thermal conductivity is significantly reduced by defects, due to increased phonon scattering.154 DFT calculations show that acetylenic linkages significantly reduce GY's thermal conductivity, which decreases with the increase in temperature due to enhanced phonon scattering, indicating strong potential for thermoelectric applications.155 The MD results indicate that Sun-GY exhibits an intrinsically low thermal conductivity (i.e., ∼24.6 W m−1 K−1 at 300 K), several orders of magnitude lower than GRA (i.e., ∼3000 W m−1 K−1), due to strong phonon scattering induced by acetylenic linkages and reduced phonon group velocities.156
Numerous studies have proposed tight-binding models to describe the pz/p* bands, aiming to enhance the understanding of the electronic structures of various GBMs and to elucidate the conditions governing the presence or absence of Dirac cones.162 Owing to its asymmetric structure, γ-GY features two characteristic edge terminations, commonly referred to as armchair and zigzag configurations. Additionally, theoretical studies indicate that γ-GY nanoribbons exhibit semiconducting properties, with armchair and zigzag forms yielding band gaps of 0.59–1.25 eV and 0.75–1.32 eV, respectively.163 GY nanoribbons with either zigzag-like or divan-like edge configurations demonstrate low band gaps in the range of 0.4 to 0.9 eV and exhibit impressive charge carrier mobilities, reaching values as high as 3104 cm2 V−1 s−1. Moreover, GDY and GDY nanotubes exhibit significantly higher distortion potential parameters than GRA or CNTs, attributed to the stronger bonding strength of triple bonds.
Experimental investigations of GDY films grown on substrates have measured their electrical conductivity and confirmed intrinsic semiconducting behavior.41 At room temperature, the electrical conductivity of GDY films was reported to be approximately 2.52 × 10−4 S m−1, indicative of semiconducting charge transport. This conductivity is comparable to that of silicon and several orders of magnitude lower than that of GRA, thereby experimentally validating the semiconducting nature of GDY. In another study, GDY has been demonstrated as a tunable electrode material, with electrochemical reactivity governed by its electronic structure and surface chemistry.164 Oxidation to graphdiyne oxide (GDYO) and subsequent chemical (cr-GDYO) or electrochemical (er-GDYO) reduction significantly enhances electron-transfer kinetics, yielding performance comparable to CNTs and GRA-based electrodes. These results highlight GDY as a promising material for carbon electrochemistry and electroanalytical applications.
Among the various parameters governing the performance of semiconducting materials, electron mobility plays a pivotal role. Notably, GBMs possess inherently high electron mobility.165,166 The electronic properties of GBMs can be notably influenced by the stacking arrangement of their layers, as variations in stacking methods introduce distinct interlayer interactions that modify the overall electronic behavior. León and Pacheco167 explored the electronic characteristics of bilayer GBMs under different stacking configurations for both metallic and semiconducting variants. Their findings revealed that in the semiconducting form, the band gap can be effectively modulated by altering the stacking arrangement. Zheng et al.168 investigated the effects of stacking on the electronic properties of GBMs, specifically focusing on bandgap and charge mobility. They found that the Bernal stacking of benzene rings led to the most energetically stable configurations for both bilayer and trilayer GBMs. Compared to single-layer GBMs, these stacked structures exhibited reduced bandgaps and demonstrated metallic characteristics, indicating a significant modulation of electronic behavior based on stacking arrangements. In these multilayer configurations, the bandgaps were notably reduced compared to the intrinsic bandgap of monolayer GBMs. Moreover, the bilayer and trilayer systems exhibited metallic behavior as a result of their specific stacking arrangements. Additional in-depth investigations have highlighted the presence of intrinsic band gaps and enhanced electronic properties in GBMs with various layering and stacking configurations.157,169,170 First-principles calculations reported a GY allotrope with a Dirac nodal line electronic structure, showing semi-metallic bands that could enable high-speed electron transport similar to GRA.171
Scalable synthesis of multilayer γ-GY was demonstrated with a direct band gap of ∼0.48 eV, experimentally confirming that GY can behave as a semiconductor rather than a metal.85 A first-principles study showed that AB-stacked γ-GY bilayers have a tunable band gap (i.e., ∼1.26–1.88 eV) controlled by biaxial strain, demonstrating how mechanical strain can modulate electronic structure for device design.182 Recent computational work predicted high carrier mobilities: electrons up to ∼104 cm2 V−1 s−1 and holes ∼103 cm2 V−1 s−1 at room temperature, making GY competitive with established 2D semiconductors for transistor channels.119
Transition-metal doping in GY-like allotropes such as B-GY can induce spin splitting and half-metallicity, making these materials promising for spintronic applications with tunable magnetic characteristics driven by strong d–p orbital coupling.186 Strain and magnetic field modeling of γ-GY predicts alterations in magnetic susceptibility and transport properties under external magnetic fields, suggesting the sensitivity of magnetic responses to mechanical and field conditions.187 Kang et al.188 performed magneto-transport experiments on nitrogen-doped GDY, showing distinct negative and positive magnetoresistance behaviors at low temperatures, indicating magnetic carrier interactions and tunable magnetic transport behaviour. Device-level theoretical work on zigzag γ-GY nanoribbons demonstrates gate-tunable fully spin-polarized currents and pure spin currents, indicating practical routes for generating and controlling spin polarization without conventional ferromagnets.189 Additionally, first-principles modeling of HGY reveals potential for collinear antiferromagnetic ground states via specific impurity adsorption strategies, offering a novel type of magnetism in 2D p-electron systems.190 These advances establish GBMs as flexible platforms for magnetism and spin transport in nanoscale devices.
GDY has been extensively characterized using multiple experimental structural techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, and AFM.204 These measurements confirm the presence of a planar porous structure with uniformly distributed sp–sp2 carbon and verify the successful synthesis and structural integrity of GDY films and powders. These methods also help correlate structural features (i.e., pore distribution and bonding environments) with the material's properties. TEM and high-resolution transmission electron microscopy (HRTEM) reveal that synthesized GDY exhibits a lamellar porous structure with a clear interlayer spacing (i.e., ∼0.365 nm) and abundant pore channels, which are key structural features that influence stability and functionality.205 The observed morphology indicates a stable layered form, although with some amorphous features due to structural defects. The γ-GY has been experimentally synthesized using a modified mechanochemical method. Structural confirmation was performed using Raman spectroscopy, XPS, XRD, SEM, and TEM, which verify the co-existence of sp and sp2 carbon and reveal the morphology and chemical bonding consistent with expected GY structures.83 Although thermal or mechanical stability tests were not emphasized in this work, the successful synthesis and stable structural identification represent an experimental milestone toward future functional testing. In a bottom-up on-surface synthesis approach on Au(111), GY- and GDY-based molecular wires were formed and structurally characterized both in situ (i.e., via scanning tunneling microscopy (STM) and XPS) and ex situ (i.e., via Raman spectroscopy).206 These structural analyses showed stable formation of sp-hybrid atomic frameworks with distinct triple-bond signatures, and the Raman spectra provided evidence of structural stability under ambient conditions, demonstrating that these atomic wires remain intact after synthesis and exposure to air.
The diverse physicochemical properties of GBMs form the foundation for their proposed technological applications. However, the practical relevance of these properties depends on how effectively they can be exploited under realistic operating conditions. In this context, the following section critically examines how material properties influence various application domains.
The promising role of GBMs in contaminant separation for water treatment has been explored in numerous studies. The investigation of GBMs as membranes has largely relied on theoretical and computational methodologies. These approaches are particularly effective for predicting material behavior, uncovering mechanisms behind complex or poorly understood phenomena and interpreting unexpected experimental findings.210 Computational modeling also provides valuable guidance for identifying optimal material configurations and supports informed decision-making in selecting suitable materials for specific applications, such as in the design of GY-based membranes. The predictive studies have been reported on GY and its related structures.
Researchers are interested in γ-GY (see Fig. 12a–h) due to its high conjugation, profusion of chemical carbon bonds, extraordinary chemical inertness, and excellent electrical, optical, and physiological properties.157 Xue et al.193 performed water desalination on five different pristine GYs using MD simulations and first-principles calculations. The resulting water fluxes displayed a linear dependence on the applied hydrostatic pressure. A performance comparison between α-GY, β-GY, and γ-GY-3 and conventional RO membranes revealed that these GYs can achieve water permeability at 100% salt rejection that is two orders of magnitude higher than that of commercial RO membranes. Thus, the monolayer γ-GY-3 membrane, exhibiting the best performance, was confirmed as a promising candidate for use in water filtration and desalination applications.
In contrast, GDY was impermeable to both water and ions even under a pressure of 250 MPa, indicating its unsuitability for desalination applications. Water transport is vital for understanding the flow behaviour at extremely small length scales in various applications. Therefore, MD simulation of continuous and spontaneous water molecule permeation via a single-layer γ-GY-3 membrane was investigated by Kou et al.211 The authors reported that the γ-GY-3 membrane is more permeable to water molecules than (5,5) CNT membranes of equal pore diameter. The net water flux through the γ-GY-3 membrane is 27.5 ns−1, compared to 13.5 ns−1 for the (5,5) CNT, despite their similar nanopore diameters. The remarkable hydraulic permeability of the γ-GY-3 membrane is mainly attributed to hydrogen bond formation, which connects the water molecules on both sides of the monolayer γ-GY-3 membrane and aids in overcoming nanopore resistance. As a result, a small single-file water structure will form, facilitating the rapid passage of water molecules across the γ-GY-3 membrane. Furthermore, a comparatively low energy barrier at the pore opening may account for the large net water flux. However, both the (10,0) and (9,0) CNTs demonstrated a higher water flux than the γ-GY-3 membrane. Lin and Buehler212 explored a different strategy by utilizing a 2D nanoweb-like GY membrane for water purification and contaminant removal from both wastewater and seawater, employing MD simulations. GY membranes exhibited water permeability values ranging from 2.9 to 4.5 × 10−9 m Pa−1 s−1, which initially increased with the number of acetylenic linkages. However, a decline in flow rate was observed when the linkage number reached 5 and 6. Additionally, the flow through the GTY membrane demonstrated optimal purification performance, ranging from 3.0 to 4.0 × 10−9 m Pa−1 s−1, while maintaining excellent contaminant rejection under the applied hydrostatic pressures. The rejection rate for all contaminants is as follows: CuSO4 > NaCl > CCl4 > C6H6. Zhu et al.213 studied the water desalination capability of the γ-GY-4 membrane. They also observed that there is a nonlinear relationship between water flux and membrane pore size; nonetheless, water flux rises linearly with pressure. Eventually, they concluded that γ-GY-4 outperformed GRA nanosheets for water desalination due to its high-water flow (i.e., 10 times greater) and salt rejection.
In other work, Kou et al.43 simulated the performance of γ-GY-3, γ-GY-4, and γ-GY-5 as membranes for water desalination. Their findings showed that γ-GY-3 had 100% salt rejection. Furthermore, γ-GY-4 nanosheet demonstrated superior salt rejection ability, with over 80% Na+ rejection and close to 100% Cl− rejection at 100 MPa pressures, which is an acceptable rate for salt rejection. This is attributed to the smaller pore size of γ-GY-4 when compared with the γ-GY-5 nanosheet. In addition, γ-GY-5 could not be employed as a membrane for water desalination due to its poor salt rejection. Progress has been achieved in utilizing GY membranes to study brine separation performance. Zhang and co-workers214 explored the efficacy of single-layer GY-n allotropes (i.e., n = 3, 4, 5, and 6) for water desalination by forward osmosis (FO). Their MD results show that γ-GY-3 performed better with high water flow (i.e., 39.15 L cm−2 h−1) and 100% salt rejection. Likewise, γ-GY-4, γ-GY-5, and γ-GY-6 membranes show comparable water fluxes slightly above or below that of γ-GY-3 but exhibit reduced salt rejection performance. The influence of membrane charge on water transport revealed that charged GY membranes consistently delivered higher water fluxes than their uncharged counterparts, indicating that charged GY-n (i.e., n = 3, 4, 5, and 6) membranes offer enhanced performance for water transport in FO systems. In summary, the study indicates that γ-GY-3 offers superior performance for brine separation, whereas GY-n (i.e., n = 4, 5, and 6) are suitable for applications where lower salt rejection is acceptable. In another research, Wu et al.215 performed MD simulations to evaluate the effect of pristine γ-GY on water purification. They looked at the influence of positive and negative charges on water permeability and demonstrated that a GY membrane with a negative charge can increase both salt rejection and water permeability. Bagheri et al.216 investigated water adsorption on the surfaces of GRA and GY nanosheets, demonstrating that GRA and GY-n (i.e., n = 1 to 5) nanosheets had distinct wettability. Their findings revealed that the water layer between the water droplets and the membrane influences various aspects of the water droplets, such as the arrangement of water molecules in various layers, the number of hydrogen bonds, and parallel forces at the interface between the water molecules and the membrane.
Research on GYs extends beyond monolayer membranes, as noted in earlier studies, with investigations also exploring the water transport and desalination performance of bilayer GY membranes. Non-equilibrium MD simulations of water-salt solutions via single and double-layer GY membranes were explored by Akhavan et al.217 This study revealed that the water flow rate through the γ-GY-4 membrane is double that of the γ-GY-3 membrane in both single- and double-layer membranes. GDY has been experimentally used to prepare filters on porous substrates for the capture of Pb2+ from an aqueous solution and showed high lead ion uptake.218 Moreover, filter materials achieved efficiencies up to ∼99.6%. According to Xue et al.193 GDY was found to be impermeable to both water and ions even under a pressure of 250 MPa, rendering it unsuitable for desalination applications. However, Baghbani et al.219 designed a pristine GDY nanosheet to study the salt rejection. The results showed that the GDY membrane exhibits 100% salt rejection at pressures. The structure of pristine GDY nanosheets contains inherent pores with optimum width for separating salt ions from aqueous solutions. This membrane shows a water permeability of 565.37 L m−2 h−1 bar−1 at 400 MPa and a salt rejection rate of 99.41%. The water permeability of pristine GDY observed in this study is comparable with that of other membranes, such as polymeric seawater RO with 1.87 L m−2 h−1 bar−1, brackish RO with 4.58 L m−2 h−1 bar−1, nanofiltration with 14.58 L m−2 h−1 bar−1, high-flux RO with 27.08 L m−2 h−1 bar−1,220 functionalized GRA with 255.41 L m−2 h−1 bar−1,221 and functionalized graphene oxide (GO) with 409.16 L m−2 h−1 bar−1.222 The aforementioned data demonstrate that pristine GDY is a highly efficient membrane for water desalination compared to other membranes due to its superior water permeability and salt rejection. However, better water permeability has been reported in other systems like CNTs,223 but when the pristine GDY was utilised as a membrane, there was no need to produce pores within the membrane for water desalination. This is a significant advantage over other single-layer membranes including GRA, boron nitride, and silicon carbide membranes.
Since nitrate ions pose a risk to the ecosystem, it is vitally important to remove them from water. In order to achieve this, Majidi and co-workers224 preferred to employ a pristine nanoporous GDY sheet with a pore density of 2.4 × 1018 pores per m2 and an incircle radius of 2.8 Å. Water naturally moves through the GDY nanopores, and the two-hydrogen-bond transient structure activates the migration of water molecules through the pores, serving as a transition state. GDY can function as a good membrane for nitrate separation, as evidenced by its high-water permeability of 6.19 L per day per cm2 per MPa with 100% nitrate ion rejection. The membrane's hydrophobicity aided in high water flux by accelerating water flow because there was no attraction connection between the water and the membrane after it passed through the holes.
The γ-GY-1 membrane with functional groups was not employed in any of the aforementioned research studies. In practical water desalination and contaminated wastewater treatment, bare GYs often become functionalized by protons or hydroxyl radicals found in the water. Hence, studying functionalization is essential for the potential application of GY in seawater desalination. Raju et al.225 evaluated the performance of both bare and hydrogenated α-GY and γ-GY membranes in desalination as a function of pore geometry, pore size, chemical functionalization, and applied pressure. The MD simulation demonstrated that γ-GY, H γ-3-GY, α-GY, and H α-GY membranes can reject more than 90% of salt ions while allowing higher water fluxes. Water permeability can reach 85 L per cm2 per day per MPa, which is three times higher than commercial seawater RO membranes and ten times higher than nanoporous GRA. As a result, they appear to be promising candidates for the desalination process among the membranes studied. Moreover, the scientists found that hexagonal pores with conical water flow (α-GY) have a higher water flux per unit accessible area than triangular pores. In another work, pristine GY-n (i.e., n = 3, 4, and 5) membranes were modified for water desalination using chemical functionalities such as hydrogen, F, carboxyl, and amine by Mehrdad and co-workers.42 According to their findings, γ-GY-3 and γ-GY-4 membranes function well in the desalination process. The effects of pore sizes and functionalizations on the GY-based membrane separation process are shown in Table 4.
| Membrane | Metal ion | Pore size (diameter) | Pore functionalization | Pressure | Ref. |
|---|---|---|---|---|---|
| α-GY, β-GY, GDY, γ-GY-3, γ-GY-4 | Na+, Cl−, Mg2+, K+, Ca2+ | Pore radius | Pristine | 0 to 250 MPa | 193 |
| α-GY-1.746 Å, β-GY-1.773 Å, GDY-1.002 Å, γ-GY-3-1.736 Å, γ-GY-4-2.470 Å | |||||
| γ-GY-3 | Na+, Cl− | γ-GY-3-0.69 nm | Pristine | 0 to 600 MPa | 211 |
| γ-GY-3, γ-GY-4, γ-GY-5, γ-GY-6 | NaCl, CuSO4, C6H6, CCl4 | γ-GY-3-3.8 Å, γ-GY-4-5.4 Å, γ-GY-5-7.0 Å, γ-GY-6-8.6 Å | Pristine | 50 MPa | 212 |
| γ-GY-3/-4/-5/-6 | Na+, Cl− | — | Pristine | 100–500 MPa | 213 |
| γ-GY-3/-4/-5 | Na+, Cl− | γ-GY-3-0.69 nm | Pristine | 0 to 350 MPa | 43 |
| γ-GY-3, γ-GY-4, γ-GY-5, γ-GY-6 | Na+, Cl− | γ-GY-3-3.8 Å, γ-GY-4-5.4 Å, γ-GY-5-7.0 Å, γ-GY-6-8.6 Å | Pristine | — | 214 |
| γ-GY-3/-4/-5 | Na+, Cl− | γ-GY-3-0.69 nm | Pristine/charged | 0 to 150 MPa | 215 |
| Bilayer γ-GY-3/-4 | Na+, Cl− | γ-GY-3-3.8 Å, γ-GY-4-5.4 Å | Pristine | 50 to 200 MPa | 217 |
| α-GY, γ-GY-2/-3/-4 | Na+, Cl− | Pore area | Pristine, hydrogenated | 0 to 1000 MPa | 225 |
| Pristine: α-GY-29.91 Å2, γ-2-GY-25.15 Å2, γ-3-GY-45.57 Å2, γ-4-GY-71.89 Å2 | |||||
| Hydrogenated: α-GY-20.48 Å2, γ-2-GY-15.72 Å2, γ-3-GY-35.31 Å2, γ-4-GY-59.90 Å2 | |||||
| γ-GY-3, γ-GY-4, γ-GY-5 | Na+, Cl− | γ-GY-3-69 Å, γ-GY-4-8.45 Å, γ-GY-5-9.92 Å | Pristine, hydrogen (–H), fluorine (–F), carboxyl (–COO−), amine (–NH3+) | 100 to 200 MPa | 42 |
| γ-GY-1 | Na+, Cl− | Pore area | Hydroxyl (–OH), fluorine (–F), carboxylic acids (–COOH) | 0 to 50 MPa | 209 |
| 12.25 Å2 to 26.09 Å2 | |||||
| GDY | Na+, Cl− | — | Pristine | 150 to 600 MPa | 219 |
| ANGMs, γ-GY membranes (γ-GY-3/-4/-5) | Na+, Cl− | Pore area | Hydrogen (–H), pristine | 50 to 250 MPa | 227 |
| ANGM-1-10 Å2, ANGM-2-19.18 Å2 | |||||
| ANGM-3-27.6 Å2, ANGM-4-37.61 Å2 | |||||
| γ-GY-3-16.88 Å2, γ-GY-4-34.03 Å2, γ-GY-5-55.6 Å2 | |||||
| Graphenylene | Na+, Cl− | Pore area | Pristine, P1-fluorinated (–F), P2-hydrogenated (–H), P3-combined fluorinated and hydroxylated (–F and –OH), P4-combined fluorinated and hydrogenated (–F and –H) | 5 to 100 MPa | 226 |
| Pristine-49.24 Å2, P1-35.94 Å2, P2-33.04 Å2, P3-22.94 Å2, P4-28.20 Å2 |
The recent MD study conducted by Azamat et al.209 explored the performance of functionalized (i.e., –OH, –F, and –COOH) γ-GY-1 nanosheet for the RO water desalination process. In their work, each pore with various functional groups has a distinct pore size that affects the water permeability. Although the –OH-functionalized membrane exhibited a greater permeability (i.e., 8953 L m−2 h−1 bar−1), salt removal was minimal in this system, especially at high hydrostatic pressures. The –OH group, being a hydrophilic group, creates more hydrogen bonds with water molecules than other systems, allowing more water molecules to pass through the pore and enhance the flow. On the contrary, using –COOH-functionalized γ-GY-1 resulted in complete salt rejection and minimal water permeability (i.e., 4235 L m−2 h−1 bar−1). The low water permeability is mainly attributed to the large size of the –COOH group and reduced pore size. The water permeability of the –OH-functionalized system was over 2.11 times more than that of –COOH-functionalized γ-GY-1.
Majidi et al.32 explored the permeation of heavy metal ions such as Hg2+ and Cu2+ across the functionalized pore of γ-GY-1 nanosheets under an external electric field. The effects of two different hydrophilic functional groups (i.e., –COOH and –NH2) were investigated by passivating at the pore edge. The –NH2- and –COOH-functionalized pores had effective pore sizes of 4.45 Å and 3.95 Å, respectively, making them suitable for the permeation of Cu2+ and Hg2+ with atomic diameters of 2.56 Å and 3.42 Å, respectively. The authors found that the electrostatic interaction between ions with the –NH2 group is higher than that of the –COOH pore, hence the –NH2 pore allowed more ions to pass through under all applied electric fields. Notably, –NH2-functionalized γ-GY-1 outperforms –COOH-functionalized γ-GY-1 in separating Cu2+ ions. However, Hg2+ ions encounter a high energy barrier when passing through the membrane, particularly in the –COOH-functionalized pore, due to their larger ionic radius and the smaller pore size of the membrane.
Balaban and Vollhardt introduced the graphenylene structure.49 In recent times, graphenylene has received a lot of interest for its pore structure and thermodynamic stability. It has been employed as a membrane to separate gases, but not to desalinate water.50 Thus, Jahangirzadeh and co-workers226 made an effort to investigate the capability of functionalized graphenylene membranes for water desalination in terms of water permeability and salt rejection by considering four different membrane-based systems (P1, P2, P3, and P4) under various external pressures. The results showed that system P1 with fluorinated pore had the greatest performance among all systems, with a permeability of 11
032 L m−2 h−1 bar−1 and 99.4% salt rejection at P = 10 MPa. Similarly, system P3 with combined functional (i.e., –F and –OH) groups at the pore had a permeability of 9293 L m−2 h−1 bar−1 and 100% salt rejection at P = 5 MPa. Although system P3, functionalized with both –F and –OH groups, exhibits greater hydrophilicity than the fluorine-functionalized P1 membrane, its permeability is lower. This reduction arises from the smaller effective pore area of P3 relative to that of P1. As a result, P1 and P3 systems can serve as effective solutions for desalination.
An innovative approach to efficient water desalination employing GY membranes was introduced. Nematipour et al.227 proposed anisotropically nanoporous GY membranes (i.e., ANGMs, n = 1, 2, 3, and 4) for water desalination and also compared its ion rejection and permeability with different γ-GY membranes (i.e., n = 3, 4, and 5). These membranes were fabricated by synthesizing nanosheets through the meta-bromination of the same molecule. During the process, the pore size of an ANGM can be controlled to remain below 1 nm by adjusting the number of triple bonds between two phenyl rings. The findings revealed that ANGMs show high permeability (i.e., 7.98–47.14 L per cm2 per day per MPa) and enhanced ion rejection. The permeability of the proposed membrane is 2–3 orders of magnitude greater than that of the RO membrane. This is mostly owing to the existence of well-engineered nanopore morphologies. In particular, ANGM-2 and ANGM-3 membranes have the maximum water permeability and complete ion rejection. As a result, using these membranes will be more suitable and cost-effective than other membranes. Recently, HsGDY achieved a very high adsorption capacity (∼2390 mg g−1) for Pb2+, significantly outperforming GDY.228 It effectively treated large volumes and removed Pb2+ from biological fluids such as blood with higher efficiency than GDY. Another study, a functionalized GDYO-3M membrane was experimentally fabricated and tested for the removal of Hg2+ from water.229 The membrane achieved >97% removal efficiency for 0.1 mg per L Hg2+ from >10 L of water within 1 h.
A wide range of first-principles studies show that GY-supported SACs are active across many electrocatalytic reactions. Representative examples include Fe@GY for the alkaline ORR,232 Fe@GY catalysing CO oxidation via an Eley–Rideal pathway with a low barrier of 0.21 eV,233 and Ru-decorated GY proceeding through a two-step CO oxidation route with the highest barrier of ≈0.7 eV.234 Boron-doped GY supporting single Co atoms (Co@B1-GY and Co@B2-GY) reached near-thermoneutral hydrogen adsorption (ΔG ≈ −0.004 eV for Co@B2-GY), highlighting exceptional HER activity, while N-doped variants (e.g., Co@N1-GY) improve stability and surface charge density to furnish additional active sites for water-splitting electrocatalysis.235,236 Beyond HER, Cr-doped GY was identified for CO2 reduction (CO2RR),237 and Ni@V-c-GY shows highly selective H2O2 generation with a very low 2e− ORR overpotential (0.03 V).238 Pyrazine functionalization of GY (TM@pyGY) further demonstrates that transition-metal anchoring (Co, Ni, Cu, Mn, Fe, Ru, Pt, Rh, Pd, and Ir) can produce bifunctional/trifunctional behaviour (HER/OER/ORR), with Pd@pyGY and Ni@pyGY among the most versatile examples.239
Transition metals such as Fe, Co, Ni, and Cu anchored on GY have been studied for direct methane-to-methanol conversion, where Co–O-functionalized GY mimicked enzymatic methane oxidation with high activity and selectivity.240 Ullah et al.241 identified Ni-GY as highly stable and catalytically active for the HER (ΔGH* = 0.08 eV). Heteroatom-doped GY (N, B, S, P, and O) further enhances the electrocatalytic performance; sp-hybridized B doping, alone or in combination with sp2-B, significantly improves the nitrogen reduction reaction (NRR) activity, achieving limiting potentials as low as 0.12 V.242 Systematic DFT and CoDOSA framework studies demonstrated the multifunctionality of SACs on doped GY substrates. Co@GY and Ni@3B-GY were identified as robust trifunctional catalysts for the ORR, HER, and OER, with AIMD simulations confirming stability at 400 K.243 Nitrogen-doped GY synthesized via mechanochemical methods also facilitated photosynthetic H2O2 production with 74% selectivity and rates of 7.47 mmol h−1 g−1.244 Li et al.245 conducted extensive DFT screening of 26 transition metals embedded in γ-GY, revealing Co, Rh, Fe, Ir, Cu, Pd, Ni, and Pt as effective unifunctional and bifunctional electrocatalysts for the ORR/OER. Multifunctional electrocatalytic activity of metals anchored on square GY (TM@S-GY) was further demonstrated, with Ni@S-GY showing trifunctional activity (HER, OER, and ORR) and Pt@S-GY, Ir@S-GY, and Pd@S-GY exhibiting strong bifunctional performance.246 TM-doped γ-GY-like BN sheets (M/γBN) also displayed promising activity for the NRR, with V/γBN showing the lowest energy barrier via the distal mechanism.247 The enhanced performance of V/γBN was attributed to an electron donation–back-donation effect, which also suppressed the competing HER activity. Additionally, incorporating Hubbard U corrections revealed a clear correlation between the adsorption energy and the bond distance. Single-atom electrocatalysts have also been applied for nitrogen reduction reactions (NRRs). Song et al.248 developed noble-metal (Rh, Ru, Ir, Os, Pd, and Pt) single atoms anchored on N-, B-, and O-doped GY (NMX@GY), with B- and O-doped GY showing higher N2 adsorption affinity. OsB@GY and RuB@GY were identified as the most effective catalysts, with Bader charge analysis indicating significant electron transfer to the adsorbed N2, facilitating activation and reduction.
First-principles investigations by Talib et al.249 on single-transition-metal atoms (STM1 = Sc–Au) anchored in GY H1 cavities confirmed structural stability via AIMD and phonon analysis. Sc1, Co1, Fe1, and Au1/GY exhibited efficient HER via the Volmer–Heyrovsky pathway, with Sc1 and Au1/GY outperforming others. Co1/GY showed excellent OER activity (0.46 V overpotential), while Rh1 and Co1/GY achieved low ORR overpotentials (0.36 V and 0.46 V). GY-supported SACs have also shown promise for selective CO2 reduction.
Liu et al.250 demonstrated that tensile-strain regulation enhances 2e− CO2RR selectivity over Co-GY by suppressing the competing HER. Constant-potential calculations and constrained AIMD confirmed the stability and high CO2RR activity of Co-GY, where the tensile strain preferentially affected *COOH adsorption relative to *H, improving CO selectivity. The effect of heteroatom doping on oxygen electrocatalysis was further elucidated by Shao and Shao,251 who studied N-doped TM-embedded GY SACs. N0–Co-GY exhibited the highest ORR activity in both acidic and alkaline media, illustrating how heteroatom engineering tunes the electronic structure and intermediate adsorption. High-throughput DFT screening of 30 TM-anchored GY monolayers (Cr–Zn and Mo–Ag) by Ye et al.252 highlighted that the catalytic performance depends on the interaction strength between intermediates and TM centers, with d-band center tuning mitigating excessively strong adsorption. Fe-GY and Mn-GY showed the best performance, achieving low overpotentials of 0.42 V and 0.59 V while retaining high thermodynamic and electrochemical stability.
Moving beyond single atoms, multi-atom clusters and triple-atom catalysts expand the product scope (e.g., C1 products in CO2RR). Triple-atom-doped systems (3Fe-GY, 3Cu-GY, 3Co-GY) show promising limiting potentials and product selectivity trends (3Cu-GY favouring CH4 and 3Cu- and 3Fe-GY favouring CH3OH), demonstrating that controlled sub-nanoscale ensembles on GY lattices can access reaction channels inaccessible to isolated SACs.253 GDY and HGY variants similarly extend functionality: GDY integration with TiO2 promotes interfacial charge transfer and suppresses recombination for improved photocatalysis;254 Au single atoms on GDY favour acetylene hydrochlorination pathways with the Langmuir–Hinshelwood route showing lower barriers than Eley–Rideal;255 and transition-metal three-atom single-cluster catalysts on GDY have been proposed as stable, high-activity alternatives to SACs.256 HGY- and GDY-supported TM anchors achieve near-Pt HER benchmarks in certain cases (e.g., Cr@HGY ΔGH ≈ −0.05 eV, AIMD stable at 300–333 K) and exhibit appealing thermoelectric/catalytic multifunctionality under strain or with non-metal dopants.257–260
GY derivatives with specialized lattice topologies also display exceptional HER performance. Motaghi and Mohammadi-Manesh261 found cobalt-anchored 6,6,12-GY to be thermodynamically stable with ΔGH* = 0.042 eV, while Jafari and Reisi-Vanani262 reported Co- and Ni-decorated 8-16-4 GY as low-cost dual-function electrocatalysts, achieving ΔGH* values of 0.03–0.09 eV and overpotentials of 0.42–0.72 V for overall water splitting. These findings collectively highlight that transition metal anchoring, heteroatom doping, and lattice engineering synergistically govern catalytic performance, enabling GY-based materials to serve as high-efficiency, stable, and multifunctional electrocatalysts for the HER and water splitting. GY-based nanostructures, including γ-, α-, and β-GY and GDY nanoribbons, have emerged as promising platforms for both single-atom and sub-nanoscale cluster electrocatalysts. Xu et al.263 demonstrated that sub-nanoscale Pt4 clusters on γ-GY exhibit strong binding due to optimal Pt–Pt/Pt–C bond length ratios, achieving CO oxidation activity comparable to Pt SACs, highlighting the potential of metal clusters on GY surfaces. For the ORR in acidic fuel cells, α-GY shows enhanced activity due to positively charged carbon sites that favor O2 and OOH+ adsorption, creating active catalytic centers.264
Beyond metal-supported systems, metal-free GY nanoribbons have shown notable bifunctional activities for the HER and ORR. Lv et al.265 combined DFT and machine learning to investigate β-GY and β-GDY nanoribbons (βGyNRs/βGDyNRs), showing that edge engineering and N-doping significantly enhance catalytic performance. In γ-GY nanoribbons, only pristine zigzag configurations without benzene terminations exhibited intrinsic activity, while others remained inactive. Introducing single nitrogen dopants revealed that sp2-N doping was more effective than sp-N, with catalytic efficiency decreasing as the doping depth increased, resulting in several N-doped γGYNRs serving as efficient bifunctional electrocatalysts.266 Similarly, GDY nanoribbons were shown to possess edge-specific active sites for bifunctional catalysis. Lv et al.267 reported that zigzag GDY NRs without benzene terminations display excellent HER and ORR activity, primarily at acetylenic linkages at the edges. Strategic N-doping further enhanced performance, with N1 doping at inner sites and N2 near edges effectively improving catalytic efficiency, while other dopant positions had negligible effects. The study highlighted the ΔEH descriptor (optimal range: −0.474 to −0.119 eV) as critical for bifunctional HER/ORR performance, confirming that appropriately engineered GDY NRs can act as high-efficiency, metal-free bifunctional electrocatalysts.
Recent advances in metal-free and heteroatom-doped GDY/GY nanostructures highlight their multifunctional electrocatalytic and energy storage potential: metal-free TAGDY shows durable acidic-media HER activity by facilitating rapid proton–electron transfer;268 GDY–GRA heterostructures with TM decoration tune Li–S battery chemistry through controlled LiPS binding and SRR catalysis;269 TH-GY is proposed as a mechanically robust, optically active 2D allotrope with potential electronic and catalytic uses;120 and dual-atom or small cluster motifs (e.g., Mo–Ni DACs, Si-doped BN-GY analogues, Ca-doped γ-GY) open pathways for the enhanced HER, N2O reduction and electronic property tuning for catalysis, storage and device applications.270–272
Ultrathin GDY-supported zero-valent palladium (Pd0/GDY) was experimentally prepared and used as an HER cathode. Pd0/GDY showed very low overpotential (i.e.,∼55 mV at 10 mA cm−2) and higher mass activity than Pt/C, with robust stability.273 Liu et al.274 synthesized GDY nanotubes and nitrogen-doped graphdiyne (NGDY) nanotubes and demonstrated their activity as metal-free electrocatalysts for the ORR, with NGDY showing enhanced onset potential and faster kinetics. Wang and Jin275 constructed a CuI-GDY/ZnAl-LDH S-scheme heterojunction that exhibited enhanced photocatalytic H2 production by efficient charge separation across GDY-based interfaces. Li et al.276 demonstrated a GDY-modified In2O3 nanocomposite for photocatalytic CO2 hydrogenation, showing significantly improved formation of C2+ hydrocarbons by enhancing photogenerated charge separation and reducing kinetic barriers in photocatalysis. Zheng et al.277 reported GDY grown with vanadium–iridium oxide (VIrOx) quantum dots forming well-defined interfaces that acted as a highly active OER catalyst with low overpotential and excellent long-term stability in alkaline electrolytes. Studies have shown that GDY integrated with metal oxides or semiconductor supports enhances the catalytic performance (e.g., improved hydrogen evolution and pollutant degradation) by improving charge separation and providing active sites.278
Taken together, the literature converges on several key, actionable insights: (i) GY-type lattices provide intrinsic binding sites and electronic tunability that stabilise single atoms and small clusters while suppressing aggregation; (ii) heteroatom doping, strain, and topology act as orthogonal levers to tune adsorption energetics, selectivity (i.e., CO2RR vs. HER), and multifunctionality; and (iii) high-throughput DFT, AIMD, and descriptor-driven screenings reliably identify promising candidates but must be complemented by targeted experimental validation to translate predicted activity and stability into practical electrocatalysts. These principles position GY and its derivatives as a fertile design space for next-generation SACs and sub-nanoscale electrocatalysts across energy conversion and storage applications.
GDY follows a similar trend, combining high capacity (LiC3) with moderate diffusion barriers (i.e., 0.18–0.84 eV).281 First-principles calculations show that the triangular pores of GDY can host three Li atoms per pore at symmetric sites, forming an alternating occupation pattern across both surfaces of a monolayer. This facilitates uniform Li distribution, with in-plane diffusion (i.e., 0.52 eV) and through-plane penetration (i.e., 0.35 eV), both energetically favorable. Such dual mobility pathways enable GDY to achieve a maximum capacity of LiC3, double that of graphite, while ensuring fast ion transport.282 Together, the high diffusion kinetics and large storage capacity of GY and GDY highlight their potential as next-generation anode materials.
Boron doping and structural engineering strategies significantly enhance the electrochemical potential of GBMs for ion batteries. Boron-doped GY exhibits improved Li binding with a capacity of ∼1130 mAh g−1,283 while multilayer α-GY and GY intercalated with Li achieve volumetric capacities up to 1589 mAh cm−3, far surpassing graphite.284 Beyond lithium, both GY and GDY support efficient Na-ion storage through low in-plane diffusion barriers (i.e., ∼0.4 eV).25 Emerging 2D carbon ene-yne has been predicted to deliver ultrahigh theoretical capacities (i.e., 2680 mAh g−1 for Li, 1788 mAh g−1 for Na), surpassing most known 2D anodes.285
External modulation offers further improvements. Strain engineering on GY enhances Li adsorption, lowers diffusion barriers, and raises capacity to 2233 mAh g−1 under 12% biaxial strain, with favorable operating voltages (i.e., 0.50 V).286 Similarly, curvature effects in γ-GY nanotubes enable orbital rearrangement, boosting capacity up to 2232 mAh g−1 for C6Li6, while also improving the Li mobility.287 B-GY offers balanced performance, with a high capacity of 525 mAh g−1, moderate voltages (i.e., ∼0.73 V), and good diffusion kinetics.288 Mechanical studies indicate that α-GY, though softer, provides greater strain tolerance, while γ-GY offers higher modulus and fracture stress; a 10% strain threshold was identified as the safe limit for enhancing storage without structural failure.289 Functional group substitution further tailors electrochemical properties, with nitro- and carbonyl-modified GYs reaching redox potentials up to 4.1 V, outperforming GRA analogues.290 Finally, α-GY nanotubes also show enhanced Li uptake (i.e., 1273 mAh g−1 for C4Li4), with curvature promoting efficient adsorption and diffusion.291 Collectively, these studies emphasize that doping, strain engineering, nanotube formation, and functionalization provide powerful routes to maximize the ion storage capacity and stability of GY derivatives. However, most capacities remain theoretical; challenges such as large-scale synthesis, electrode integration, and cycling durability must be addressed before their translation into practical ion batteries.
Recent computational studies highlight the versatility of GY-based materials (GYs, GDYs, and derivatives) as high-capacity anodes across a range of ion batteries. For Na-ion systems, layered GDY demonstrated stable Na intercalation up to x = 0.61 (i.e., 1237 mAh g−1), nearly 35 times the capacity of graphite, while α-GY achieved an even higher theoretical capacity of 1396 mAh g−1 with optimal OCV (0.81 V) and low diffusion barriers (i.e., 0.18–0.96 eV).292,293 Similarly, T4,4,4-GY exhibited exceptional Na mobility with a semiconductor-to-metal transition upon adsorption.294 PG-yne extended this trend, it can host up to eight Li/Na ions, delivering a theoretical capacity of 680 mAh g−1, with low diffusion barriers (i.e., ≤0.50 eV), low open-circuit voltages, and enhanced electronic conductivity, surpassing many conventional 2D anodes, particularly for Na-ion systems.28 For multivalent systems, boron–nitrogen-substituted GY (BN-yne) outperforms pristine GY for Ca-ion batteries, offering lower migration barriers (i.e., 4.3 vs. 5.9 kcal mol−1) and higher diffusion coefficients, indicative of faster charge/discharge kinetics.295 similarly, 3D porous phosphorus-GDY (3D-PGDY) exhibits ultrahigh specific capacities of 1064.56 mAh g−1 (K) and 2129.12 mAh g−1 (Ca) with minimal diffusion barriers and negligible volume expansion, highlighting the advantages of 3D architectures and sp-hybridized frameworks for multivalent ion storage.296 HGY demonstrates exceptional performance for K-ion batteries, balancing high capacity (i.e., 651 mAh g−1), moderate volume expansion, and good ionic conductivity, though lower structural stability can limit ion mobility; hybridization with more robust materials like GRA is suggested to optimize diffusivity for broader metal-ion battery applications.26
GY derivatives have emerged as promising cathode and anode materials for advanced metal-ion batteries, exhibiting high capacity, structural stability, and efficient ion transport. GDY has been proposed as an effective cathode for aluminum dual-ion batteries (ADIBs), with DFT and AIMD studies demonstrating rapid AlCl4− diffusion, thermodynamic stability, and a high theoretical specific capacity of 186 mAh g−1, about three times that of graphite, alongside strong cyclic durability.297 Further investigations of α- and γ-GY as Al-ion battery cathodes reveal ample adsorption sites for AlCl4−, high open-circuit voltages (i.e., 2.18–2.22 V), and excellent structural resilience, with α-GY exhibiting minimal volume expansion (186%) and extremely low expansion energy (i.e., ∼0.003 eV Å−2), favoring reversibility and cycling stability.298
For anode applications, 3D porous PGY structures and sandwich GRA/PGY/GRA architectures facilitate multivalent ion storage with low migration barriers and high thermal/mechanical stability. Li ions can traverse multiple pathways, whereas larger Na and K ions migrate through larger pores, yielding energy barriers of 0.18–0.43 eV in 3D-PGY, which further reduced to 0.12–0.37 eV in the sandwich configuration. These materials deliver theoretical specific capacities up to 558 mAh g−1 with favorable open-circuit voltages, highlighting the versatility of GY-based architectures for Li-, Na-, and K-ion battery anodes.29
A free-standing HsGDY film was experimentally synthesized via an in situ coupling reaction and used as a flexible anode for lithium-ion and sodium-ion batteries.299 The HsGDY electrode delivered large reversible capacities (∼1050 mAh g−1 for Li-ion and ∼650 mAh g−1 for Na-ion) at 100 mA g−1, along with good rate performance and cycling stability, attributed to its porous π-conjugated structure and facilitated ion transport. GDY/exfoliated graphene (EG) composite electrodes prepared by solvothermal methods were applied in Li-ion cells.300 The composite showed a reversible capacity of ∼1253 mAh g−1 after 600 cycles at 0.5 A g−1, and maintained ∼324 mAh g−1 after 2000 cycles at 5 A g−1, attributed to enhanced conductivity. GDY was experimentally integrated with GRA in a GDY/Gr/GDY sandwich structure and tested as an anode for potassium-ion batteries.301 This composite electrode showed enhanced capacity, rate capability, and cycling stability compared to bare GDY, demonstrating practical potassium storage performance.
Three-dimensional porous HsGDY was prepared via an interface-assisted synthesis and used as an anode in LIBs.302 The electrode exhibited large reversible capacity (i.e., ∼930 mAh g−1 after 100 cycles at 1 A g−1), excellent cycling (i.e., ∼720 mAh g−1 after 300 cycles), and good rate capability, via expanded interlayer spacing and enhanced ion accessibility. HsGDY has been experimentally investigated as a cathode additive or interlayer in lithium–sulfur (Li–S) batteries to mitigate the polysulfide shuttle and improve performance.303 Heat-treated HsGDY showed enhanced sulfur trapping and improved cycle life, though the mechanism was linked to structural changes rather than direct chemical interaction during cycling. HsGDY aerogel was used as a host for molten Li metal to fabricate composite Li@HsGDY anodes, where the hierarchical pore structure and lithiophilic nature enabled improved lithium-ion transport and suppression of dendrite formation.304 A composite of tin dioxide with GDY (SnO2/GDY-400) was synthesized and applied as an anode in both lithium-ion and sodium-ion batteries.305 The high conductivity of GDY mitigated SnO2 agglomeration and volume expansion, resulting in excellent specific capacities (i.e., ∼1478 mAh g−1 in LIBs) and high capacity retention over long cycling. Collectively, these studies underscore the tunability of GBMs for both cathode and anode applications, combining high capacity, ion mobility, and structural resilience, making them strong candidates for next-generation rechargeable metal-ion batteries.
Computational studies have highlighted the remarkable selectivity of GBMs. For instance, defect-free hydrogenated α-GY achieved complete H2/CH4 separation with H2/N2 selectivity of ∼700, although performance diminished at higher temperatures and in the presence of defects.308 Functionalization strategies (i.e., –OH, –F) were shown to enhance CH4/H2S separation, particularly at zero applied pressure, emphasizing the role of edge chemistry in tuning selectivity.309 Similarly, among the γ-C4X (i.e., X = O, S, and Se) family, γ-C4O was predicted to be structurally stable with extremely high H2/CH4 selectivity (i.e., 1019), though such idealized values may be difficult to replicate experimentally.310 Hybrid designs, such as GY-based mixed matrix membranes (GY-polypyrrole), demonstrated adsorption selectivity (i.e., H2O > CO2 > O2) and optimal O2 diffusion at ∼15% filler loading, underscoring the delicate balance between permeability and filler dispersion.311 Notably, γ-GY-3 showed extraordinary H2 permeance (∼107 GPU) while excluding larger hydrocarbons like C2H6, outperforming both GRA and other 2D membranes.312 Despite these promising predictions, the exceptional selectivity and permeance of GBMs largely stem from idealized MD and DFT models, with performance highly sensitive to defects, pore chemistry, and operating conditions. Bridging this simulation-experiment gap remains the key challenge, particularly in synthesizing large-area, defect-controlled GY membranes and validating their separation efficiency under realistic mixed-gas feeds.
GDY has emerged as a promising membrane for H2 extraction from syngas due to its intrinsic triangular pores, which offer size- and energy-dependent selectivity. Computational studies reveal that H2 faces very low permeation barriers (i.e., ∼0.1 eV), while CO and CH4 encounter significantly higher resistances (i.e., 0.33 eV and 0.72 eV, respectively).313 Importantly, selectivity can be tuned through pore size engineering, with permeation barriers decreasing exponentially with the increase in pore diameter.314 Temperature and pressure exert strong influences: H2 flux rises with temperature (i.e., 7.3 to 9.4 g cm−2 s−1 between 300 and 500 K), whereas CO and CH4 require extreme thermal or pressure conditions (i.e., >1100 K or ∼200 MPa) to penetrate, confirming GDY's intrinsic molecular sieving capability.315 Electrostatic tuning further enhances selectivity, as positive charging increases diffusion barriers for CO and CH4, yielding up to 100-fold improvements in H2/CO separation.316
Beyond syngas purification, GDY shows chemical robustness (i.e., oxidation barrier ∼1.97 eV) and versatile separation potential. Meng et al.317 demonstrated its strong O2 selectivity against toxic gases (i.e., Cl2, HCN, SO2, and H2S), while engineered structures such as dumbbell-shaped GYs318 and rhombic-GY314 expand the design space for tailored gas sieving. Chemical modification also plays a decisive role: GDY-F and GDY-O achieved efficient CO2/N2/CH4 separation, with GDY-O highly selective for CO2/N2 below 300 K.319 Zhou et al.320 fabricated suspended GDY membranes over micrometer-scale apertures and measured gas flow rates through them. They observed fast permeation of light gases (i.e., He, H2, Ne) with suppressed flow of heavier noble gases, indicating size-dependent gas transport through GDY nanopores. For CO2/CH4 separation, nanoporous GDY exploited geometric effects, linear CO2 could align with triangular pores, lowering barriers relative to spherical CH4, whereas boron-GDY's larger hexagonal pores lost selectivity.321 Quantum effects also emerge: Rafiei et al.322 reported exceptionally high O2/N2 selectivity (i.e., 106 at 100 K) due to differences in transmission barriers coupled with zero-point energy contributions. Strain engineering offers another pathway; rhombic N-GDY under 3–3.5% zigzag tensile strain achieved ultrahigh CO2/N2 selectivity (i.e., 103–104) with high permeance.323 Collectively, these findings underscore GDY's unique combination of intrinsic porosity, chemical stability, and tunability through functionalization, charge doping, or strain. However, most reports rely on DFT and MD predictions under idealized conditions. Realizing GDY's promise in industrial gas purification demands scalable synthesis of defect-controlled monolayers, validation under mixed-gas feeds, and long-term stability tests.
Recent computational studies have extended gas separation research to GTY and graphenylene membranes. Apriliyanto et al.324 demonstrated that GTY multilayers combine permeation and adsorption mechanisms, with single layers showing a modest CO2/N2 selectivity (i.e., 4.25), while bilayers improved the separation performance for post-combustion capture. Trilayers further enhanced CO2 uptake due to interlayer adsorption, highlighting GTY's tunability and competitiveness with other carbon nanomaterials in emission control. Rezaee and Naeij325 reported graphenylene-1 membranes as structurally stable and exceptionally selective, with remarkably low energy barriers for H2 and He transport. Predicted selectivities reached extreme values (i.e., 1027 for H2/CO2 and 1046 for H2/CH4), with permeance surpassing industrial benchmarks, especially at elevated temperatures. While these findings position GTY and graphenylene as highly promising candidates for CO2 capture and H2 purification, the extraordinary selectivities are largely derived from idealized MD and DFT models, and their experimental translation hinges on scalable synthesis and defect control.
DFT and MD studies confirm the strong and orientation-dependent adsorption behavior of GY. Nikmanesh et al.326 found CH4 adsorption to be most favorable in the UP configuration (i.e., −0.594 eV), indicating stable physisorption. Metal functionalization further enhanced performance, and Al-decorated γ-GY displayed strong nitrobenzene binding (i.e., −1.18 eV), substantial charge transfer (i.e., 0.57 e), and fast recovery (i.e., 2.4 s at 450 K), ensuring both selectivity and reusability.328 Singh et al.329 similarly observed strong chemisorption and HOMO–LUMO gap reduction during SO2 adsorption, confirming stable interaction and electronic sensitivity. Beyond pristine GY, heteroatom doping and hybridization significantly expand its sensing versatility. Au-doped BN-yne nanosheets exhibited improved hydroxyurea detection efficiency, electrical conductivity, and rapid recovery (i.e., 1.36 s),330 while γ-GY-like SiC nanoflakes with a 1.749 eV bandgap showed selective physisorption and strong charge transfer toward CNCl, underscoring their potential for toxic gas detection.331
Recent studies further highlight the tunability and superior sensing potential of GY through functionalization and heteroatom doping. Lakshmy et al.328 demonstrated that Al anchoring enhances adsorption energy and charge transfer compared to pristine γ-GY, increasing work-function sensitivity by 10% and maintaining thermal stability under AIMD conditions, ideal for reusable nitrobenzene sensors. Similarly, Zhang et al.332 showed that N-doped GY exhibits distinct conductivity modulation for volatile organic compounds, with maximum sensitivity to acetone (i.e., 81%), highlighting its applicability in biomedical diagnostics such as non-invasive diabetes detection. The combination of physisorption and measurable conductance modulation highlights the potential of N-GY for biomedical diagnostics, including breath-based acetone sensing for diabetes detection.
Surface functionalization and heteroatom doping further broaden the potential of GY in environmental and molecular sensing by enhancing its electronic responsiveness, selectivity, and adsorption capability. Sakr et al.333 demonstrated that γ-GY functionalized with electron-withdrawing groups (i.e., –NO2, –COOH, and –CN) exhibited improved adsorption affinity and bandgap reduction, following the stability order of Gp–NO2 < Gp–COOH < Gp–CN < Gp–SOH < Gp–CH3. Among these, –NO2 functionalization showed the strongest interaction with heavy metal ions (i.e., Hg2+, Pb2+, and Cd2+) and a highly stable electronic structure, making it a strong candidate for wastewater monitoring. Similarly, Movlarooy and Nooranbjar334 revealed that α-GY exhibits selective chemisorption of NO, O2, and Cl2, whereas CO2 and F2 remain weakly physisorbed, demonstrating that charge transfer-induced bandgap modulation enables high selectivity toward oxidizing gases.
Beyond chemical sensing, GY's mechanical flexibility and wide elastic strain range offer efficient electromechanical coupling, making it suitable for temperature and strain sensing.37 Its ability to undergo reversible deformation without lattice degradation underpins its application in flexible and wearable sensors. GDY, in particular, combines tunable electronic and mechanical properties, exhibiting strain- and temperature-dependent bandgap modulation. Thermally induced tensile strain increases the bandgap, generating measurable voltage responses and enabling self-regulating behavior in adaptive electronic systems such as thermally controlled transistors.37
GDY has been used as a support platform for electrochemical sensors such as Pt-nanoparticle-decorated GDY used to detect bisphenol AF with excellent sensitivity and low detection limits (i.e., ∼0.09 µM).335 Recently, γ-GY films synthesized via chemical exfoliation have been demonstrated as functional room-temperature chemiresistive sensors, showing strong responses to low concentrations of NO2 and high selectivity at room temperature, indicating real gas sensing capability in experiments.336 GDYO has been experimentally employed in flexible, self-powered humidity sensors on fabric substrates, exploiting moisture adsorption to generate measurable electrical output, demonstrating the material's utility in real sensing systems.337 HsGY sheets integrated with WO3 nanoparticles have been experimentally developed for NO gas sensing at low temperatures, showing improved response values compared to pure WO3 due to the conductive support of HsGY.338
Computational studies further emphasize the role of dopant engineering in enhancing the sensing efficiency of GDY. Xu et al.339 found that pristine GDY interacts weakly with temozolomide, whereas B-doped GDY shows much higher adsorption energies (i.e., −21.92 to −45.44 kcal mol−1) and stronger charge transfer, demonstrating improved molecular sensitivity. Similarly, Kadhim et al.340 reported that Si-doped GDY enhances cisplatin adsorption (i.e., −49.39 kcal mol−1) while improving conductivity, making Si-GDY a promising nanosensor for drug detection. Extending this concept, Lakshmy et al.341,342 showed that transition-metal-doped HGY, particularly Sc-doped variants, exhibits robust adsorption, strong charge transfer, and AIMD-verified thermal stability for catechol and NH3 detection. Collectively, these findings reveal that strategic functionalization and dopant engineering, especially with Sc, Si, and B, significantly strengthen GDY and HGY's electronic sensitivity, adsorption strength, and thermal resilience. This establishes them as highly adaptable materials for next-generation nanosensors targeting environmental pollutants, toxic gases, and biomedical analytes.
The most stable configuration for NO adsorption was at the H2 site (see Fig. 13a) with nitrogen facing downward, exhibiting a binding energy of −0.16 eV. For NO2, the highest binding energy (i.e., −0.17 eV) was also observed at the H2 site, but with nitrogen oriented upward. Madhumitha et al.345 explored the adsorption behavior of the nucleobases guanine and cytosine on pristine γ-GY sheets. As illustrated in Fig. 13b, cytosine was adsorbed at positions P1 and P2 through interactions involving oxygen and hydrogen atoms, respectively. Similarly, Fig. 13c shows guanine adsorption at positions P3 and P4 via oxygen and hydrogen atoms. The calculated adsorption energies indicated that configurations involving oxygen interactions P1 (i.e., −0.637 eV) for cytosine and P3 (i.e., −0.619 eV) for guanine were more energetically favorable than their hydrogen-interacting counterparts, P2 (i.e., −0.363 eV) and P4 (i.e., −0.460 eV). To identify the most stable configuration for a single CS2 molecule adsorbed on a GY sheet, Zhang and Derakhshandeh347 investigated the adsorption behavior of CS2 gas on pristine GY using several plausible initial adsorption geometries.
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| Fig. 13 (a) Representation of pristine GY with selected binding sites.344 Adsorption behavior of nucleobases on GY nanosheets: (b) cytosine adsorption on pure γ-GY at P1 and P2 and (c) guanine adsorption on pure γ-GY at P3 and P4.345 (d) Structure of GDY with possible adsorption sites.346 | ||
Ebadi et al.346 investigated the adsorption behavior of methanol and CO on pristine GDY by analyzing three possible adsorption sites (see Fig. 13d), each with different molecular orientations. For the H and h sites, the C–O bond of the adsorbates was positioned either perpendicular (C-head and O-head) or parallel to the GDY surface. In the case of the acetylenic link (i.e., Position A), only parallel configurations with favorable interaction energies were considered. Their findings revealed that methanol favored the parallel orientation over perpendicular ones, while CO exhibited a preference for the perpendicular C-head configuration. Among all the adsorption sites evaluated, the H site emerged as the most energetically favorable for both methanol and CO. Quej et al.348 explored hydrogen adsorption on γ-GY and γ-BNyne using DFT-D3. Results indicated that H2 adsorption does not significantly affect their structural or electronic properties, confirming material stability under hydrogen exposure. These findings suggest γ-GY and γ-BNyne as promising candidates for applications in nanosensors, nanomedicine, and hydrogen storage.
Metal doping further amplifies adsorption and sensing performance. Zhang and Derakhshandeh347 reported that Al-doped γ-GY shows significantly stronger CS2 adsorption, with exothermic doping at two carbon sites (i.e., −6.38 and −5.61 eV), highlighting the site-dependent efficacy of doping (see Fig. 14a and b). Yang et al.353 demonstrated that Fe doping in γ-GY substantially increases adsorption energies for various gases (CO, O2, NO, NO2, and SO2), with values up to −3.706 eV depending on the doping site (Fig. 14c), indicating markedly enhanced sensing capabilities. Collectively, these studies illustrate that element doping, whether with light atoms (i.e., B, N, O, Si, and Al) or transition metals (Fe), can strategically tune GY's electronic structure, local charge distribution, and adsorption sites, thereby optimizing its interaction with diverse chemical species. The choice of dopant, its position, and the nature of the target molecule govern the extent of adsorption enhancement, making doped GY a highly versatile platform for gas sensing, toxic molecule detection, and adsorption-driven applications.
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| Fig. 14 Adsorption behaviour of the CS2 molecule on (a) pristine and (b) Al-doped GY.347 (c) Four possible sites of γ-GY for Fe atom-doped C1, C2, H1 and H2.353 | ||
Zeng et al.354 examined rare base (RB) adsorption on pristine and transition metal (i.e., Fe, Co, and Ni)-doped γ-GY using DFT. While pristine γ-GY showed weak physisorption, TM-doping enabled stronger chemisorption, enhancing selectivity and sensitivity. Notably, Ni-GY exhibited high selectivity, whereas Fe-GY demonstrated excellent responsiveness, highlighting TM-GY nanosheets as promising candidates for RB detection and biosensor design. Li et al.355 investigated rare base-pair adsorption on pristine and B/N-doped γ-GY using DFT. Results showed that B-doping enhanced adsorption stability compared to pure and N-doped γ-GY. Translocation time analysis confirmed that rare base-pairs can be effectively distinguished, while sensing response indicated that B-GY favored G-5hmCyt adsorption and N-GY favored G-Cyt. These findings highlight B/N-doped γ-GY nanosheets as promising candidates for biosensor development in epigenetic detection.
Another system of interest for H2 storage is Li-decorated GY, benefiting from lithium's extremely low atomic mass.359 Light metal decoration further improves performance. Li-GY exhibits exceptional hydrogen storage potential owing to lithium's low atomic mass and strong polarization capability, reaching up to 18.6 wt% storage with an optimal H2 binding energy (i.e., ∼0.2 eV).360 Kumar and Dhilip Kumar361 advanced this concept using a porous Li-decorated metal–GY framework (MGF-Li8), where each Li atom adsorbs three H2 molecules via charge-induced polarization, forming MGF-Li8–H24. The interaction leads to H–H bond elongation and decreasing adsorption energy (i.e., 0.40–0.20 eV) with the increasing loading, indicating reversible physisorption. MD simulations further verified the high reversibility of the system and a practical hydrogen storage capacity of 6.4 wt% under ambient conditions.
Recent computational investigations highlight the exceptional hydrogen storage potential of metal-decorated GY derivatives due to their uniform pore networks, strong metal anchoring, and favorable adsorption energetics. Hussain et al.362 demonstrated that boron-doped graphdiyne (BGDY) provides an ideal platform for light-metal functionalization, as its uniformly distributed pores enable stable incorporation of Li, Na, K, and Ca atoms with high binding energies and minimal clustering. Substantial charge transfer from dopants to the BGDY matrix induces positive polarization, enhancing H2 adsorption through electrostatic interactions. The resulting storage capacities, 14.29, 11.11, 9.10, and 8.99 wt% for Li-, Na-, K-, and Ca-BGDY, significantly surpass those of most 2D materials, with adsorption energies (i.e., 0.17–0.40 eV per H2) ideally suited for reversible storage. Liu et al.363 revealed that Li-decorated C68-GY achieves a stable and dispersion-resistant configuration, where strong Li-substrate bonding prevents aggregation. The system exhibits a gravimetric storage capacity of 8.04 wt% with an optimal adsorption energy (i.e., −0.227 eV per H2), driven by electrostatic polarization and orbital hybridization between Li and H2. Similarly, Gao et al.34 reported a Li-decorated HGY exhibiting a storage capacity of 12.8 wt%, with each Li atom adsorbing four H2 molecules via polarization-driven physisorption, and excellent thermodynamic reversibility verified through AIMD simulations.
Transition-metal functionalization further enhances the binding strength and thermal stability. Singh et al.364 showed that Y-decorated HGY stores up to seven H2 molecules per Y atom (i.e., 9.34 wt%), exceeding the U.S. DOE target, with adsorption mediated by Kubas-type interactions and stability retained up to 438 K. Likewise, Zr-decorated γ-GY30 demonstrated strong metal anchoring, high desorption temperature (i.e., 574 K), and substantial gravimetric capacity (i.e., 7.95 wt%), with diffusion barriers effectively preventing Zr clustering, conditions particularly favorable for fuel-cell applications. Collectively, these findings affirm that metal-decorated GY frameworks, especially Li-, Y-, and Zr-functionalized variants, combine high gravimetric density, optimal adsorption energies, and robust thermal reversibility, positioning them as promising candidates for next-generation solid-state hydrogen storage materials.
From a quantum transport perspective, ab initio studies reveal that GY molecules function effectively as active elements in single-electron transistors operating under Coulomb blockade conditions.365 DFT simulations highlight stable charge configurations and significant polarization-induced renormalization effects, with gate coupling values comparable to GRA and benzene-based systems, but notably higher than fullerene counterparts.365 These findings underscore the promise of GY-based frameworks for high-performance nanoscale transistors, where controllable band gaps, high mobility, and quantum-level tunability collectively address the limitations of silicon-based technologies.
GDY introduces additional functionality owing to its electric-field-dependent band gap. Under a strong gate bias, GDY transitions from semiconducting to metallic behavior, facilitating efficient channel modulation.37 Experimental studies have confirmed its semiconducting nature with a conductivity of 2.516 × 10−4 S m−1,58 while theoretical models predict superior performance due to its low electron effective mass and strong π-conjugation. Simulated GDY-FETs with aluminum electrodes exhibit an on/off ratio of 104 and high on-state current (i.e., 1.3 × 104 mA mm−1 at 10 nm channel length),367 highlighting its capability for high-speed nanoscale electronics. Among GY allotropes, γ-GY-1 demonstrates excellent compatibility with tunneling FET (TFET) architectures. Rouzkhash et al.368 reported that γ-GY-1 nanotubes (GYNTs) effectively suppress ambipolar behavior and improve subthreshold swing (SS), achieving values as low as 5 mV dec−1 for 9.6 nm 3AGYNT-TFETs with an ultrahigh on/off current ratio of 1.6 × 1010 at VDD = 0.2 V. These results, supported by the deformation potential and NEGF-DFTB analyses, indicate strong electron–phonon coupling and ballistic transport behavior, positioning GYNT-TFETs as viable low-power alternatives to silicon MOSFETs.
Heterostructure integration further enhances transistor performance. First-principles studies on GY/GRA van der Waals heterostructures reveal n-type ohmic contact formation with zero Schottky barrier height (SBH) and tunable electronic behavior under vertical electric fields.369 The seamless charge transfer between GRA and GY layers facilitates efficient electron tunneling, offering design flexibility for all-carbon 2D FETs. Similarly, α-GY nanoribbon-based FETs have shown near-compliance with the International Roadmap for Devices and Systems 2022 targets, achieving an SS of 73.9 mV dec−1 and low dynamic power dissipation (i.e., 0.00864 fJ µm−1).366 Interestingly, defect engineering, via single or edge vacancies, improves SS (i.e., 59.8–63.3 mV dec−1) at the expense of higher power dissipation, reflecting the tunability–stability trade-off in GY-based electronics. Together, these studies highlight the promise of GY and GDY for next-generation FETs, combining tunable band structures, high carrier mobility, and compatibility with quantum-scale device operation. Their structural diversity and integration potential mark a significant advancement beyond silicon and GRA platforms toward fully carbon-based nanoelectronics.
GDY thin-film transistors exhibit efficient and reversible performance modulation via light and thermal stimuli, delivering switching ratios up to 103–104 and enhanced conductivity (i.e., ∼1.5 × 104 S m−1), underscoring their suitability for logic and flexible electronic applications.370 An interfacial method enables rapid synthesis of nitrogen-substituted GY films that act as efficient semiconductors in FETs, achieving carrier mobilities up to 9.8 cm2 V−1 s−1 at low operating voltages, demonstrating strong potential for GY-based electronic devices.371 GDY has been used as the active charge carrier layer in FET biosensor devices, where non-covalent functionalization preserved electrical properties and enabled ultrasensitive detection of biomolecules with high on/off ratios (i.e., >104).372 A noncovalent grafting strategy enables GDY to act simultaneously as a charge-transport layer and bioaffinity substrate in FET biosensors, allowing stable immobilization of receptors while preserving electrical properties for ultrasensitive detection.372 GDY particles have been experimentally incorporated as nano-floating-gate materials in organic field-effect transistor (OFET) memory devices.373 When blended into a polymer matrix, these OFETs show bipolar memory behavior with a large memory window (i.e., up to ∼86 V), long retention (i.e., >104 s), and high ON/OFF current ratios (i.e., ∼7.5 × 105), demonstrating GDY's capability as a functional charge-trapping medium in FET-type devices.
Beyond mechanical reinforcement, GY incorporation significantly improves functional properties. Luo et al.374 reported that GY/polypyrrole (GY/PPy) composites exhibit enhanced thermal conductivity, with 20 wt% GY loading achieving ∼90% higher conductivity than pure PPy, attributed to favorable flake aspect ratios and enhanced electronic transport. Similarly, in mixed-matrix membranes (MMMs), GY acts as a selective barrier and transport modulator. Luo et al.311 demonstrated that the incorporation of GY into MMMs optimizes gas permeation, with adsorption capacities following H2O > CO2 > O2, and oxygen diffusion reaching a maximum at ∼15 wt% GY. These findings underscore GY's dual role as both a mechanical reinforcer and a functional nanofiller, offering a versatile strategy to tailor composite properties for advanced structural and separation applications.
GDY was used as an ultralow-loading filler in PVDF composites, demonstrating its strong potential for high-performance polymer thermal management and electronic cooling applications.375 Experimental studies have fabricated γ-GY/graphitic carbon nitride quantum dot (CNQD) hybrid composites with epoxy matrices, showing improved tensile strength (i.e., ∼27% enhancement) and thermal properties compared to pure epoxy.106
Although GBMs have been proposed for diverse applications, their practical promise varies substantially when evaluated through the lens of manufacturability, performance tolerance, and integration complexity. Applications such as membrane-based separation, catalysis, and electrochemical energy storage currently represent the most viable directions because they can operate effectively with multilayer, polycrystalline, and defect-containing GY structures, which are the dominant products of scalable synthesis methods. In membrane-based separations, for instance, selective transport is governed primarily by local pore chemistry and size, rather than long-range crystalline coherence, while during catalysis and in batteries, defects and heteroatom doping can actively enhance adsorption, charge transfer, and reaction kinetics. By contrast, nanoelectronic applications, including transistors and field-effect devices, demand stringent material requirements such as wafer-scale continuity, atomically precise thickness control, minimal defect densities, and stable metal-contact interfaces. These requirements are fundamentally misaligned with the current state of GY synthesis, which cannot yet deliver large-area, single-crystalline films with reproducible electronic properties. Similarly, hydrogen storage and sensing applications remain limited by intrinsic material constraints: hydrogen binding energies in GY are often insufficient for reversible storage under ambient conditions, while sensing performance is sensitive to environmental fluctuations and structural variability, complicating reproducibility and scale-up.
Coupling the intrinsic properties, such as unique pore structure and fully conjugated networks, with rational surface engineering approaches, including elemental doping and biomolecular functionalization, further broadens the applicability of GDY biomaterials by enabling tailored interactions with biological systems (i.e., enhanced cellular uptake and reduced nonspecific cytotoxicity), suggesting favorable biocompatibility under controlled conditions.378 Preliminary in vitro investigations have shown that GDY demonstrates relatively low cytotoxicity toward mammalian cell lines at moderate concentrations, with cell viability strongly dependent on dosage, exposure time, and surface functionalization.379 The presence of uniformly distributed pores in GBMs has been proposed to reduce membrane disruption effects commonly observed in GBMs, potentially improving biocompatibility in drug delivery and biosensing applications.380
Experimental work has demonstrated that GDYO can undergo biological degradation, producing quantum dots that elicit a minor foreign-body response in vivo, indicating that GBMs may not be inherently inert but do engage dynamically with biological environments, with implications for both safety and clearance pathways.381 Moreover, acute toxicity to aquatic organisms such as microalgae has been reported, with GDY shown to influence gene expression associated with lipid metabolism and autophagy, and exhibit dose-dependent effects in larvae development models, highlighting species-specific sensitivities and ecological risk potentials.382 These findings indicate that although GBMs may exhibit lower cytotoxicity than materials such as GO under certain conditions, they still interact with biological systems in nontrivial ways, highlighting the need for careful evaluation of their biological effects. Furthermore, the biological impact of GBMs is strongly influenced by physicochemical factors such as size, shape, surface chemistry, oxidative state, dispersion, and functional groups.
Environmental impact assessments of GBMs are even more limited but critically important, given their proposed use in water purification, ion separation, and catalytic applications. Early eco-toxicological evaluations suggest that GDY exhibits lower toxicity toward aquatic microorganisms than GO, potentially due to its lower defect density and reduced generation of ROS. However, concerns remain regarding long-term persistence, bioaccumulation, and degradation pathways in natural ecosystems. The high chemical stability of sp–sp2 carbon frameworks may lead to prolonged environmental residence times, necessitating further investigation into their life-cycle impact.
While recent computational studies consistently demonstrate the intrinsic structural integrity, thermal robustness, and mechanical strength of various GY allotropes, these investigations are largely limited to idealized or short-timescale conditions and do not offer systematic, long-term degradation assessments under realistic chemical and mechanical environments relevant to practical membrane applications. Latest atomistic simulations and DFT studies indicate that emerging GY structures, such as TH-GY, exhibit substantial mechanical resilience, characterized by high Young's modulus values (i.e., ∼263–356 GPa) and confirmed dynamical stability from phonon dispersion analyses and AIMD at elevated temperatures.120 These findings suggest a mechanically robust lattice capable of withstanding applied stress, which is essential for maintaining membrane integrity under pressure. Nevertheless, these assessments are primarily confined to short-timescale simulations and intrinsic material properties and do not address long-term mechanical deformation, fatigue, or failure mechanisms under continuous membrane operation. Detailed MD studies of GY variants such as 8-16-4-GY reveal that vacancy defects, microcracks, and elevated temperatures strongly influence mechanical behavior, with crack formation leading to pronounced degradation in mechanical performance and pre-existing defects promoting brittle fracture.384 The fracture in 8-16-4-GY initiates with the breaking of ethylene bonds once the strain approaches a critical threshold of about 0.29. While these findings underscore the critical role of realistic structural imperfections in governing mechanical durability, they do not extend to correlating such defect-driven degradation with long-term operational failure modes over extended service lifetimes relevant to membrane applications.
In energy storage systems, especially Li ion and Li–S batteries, GBMs have been explored both as active electrode components and as protective interlayers. Atomistic simulations suggest that nanoporous GY and GDY layers can facilitate Li ion transport while preventing electrolyte penetration to electrodes, contributing to enhanced safety and performance in solid-state configurations.385 However, ensuring that these materials retain their structural integrity during extensive cycling is critical: repeated lithiation/delithiation, ion intercalation, and volumetric changes can stress the carbon lattice, potentially leading to microcracks, delamination, or pore collapse. Although direct experimental studies on GBM cycling stability remain limited, analogous work on other 2D carbon materials indicates that mechanical deformation and fracture can significantly contribute to capacity fading and performance loss over time when volume changes are large.386 In composites such as GDY grown on scaffold materials, enhanced cycle stability has been observed, but long-term studies (i.e., hundreds to thousands of cycles) are needed to validate durability claims under realistic conditions.387
Understanding the degradation mechanisms, whether chemical (i.e., oxidation and hydrolysis in aqueous environments), mechanical (i.e., crack formation and pore coalescence), or electrochemical (i.e., SEI formation, volume changes during cycling), is essential for rational GBM design. For example, carbon materials in membrane or battery environments can undergo surface oxidation or react with electrolyte species over time, leading to the loss of pore integrity or mechanical weakening. Insights from studies on GRA and related materials show that such degradation pathways can be mitigated by surface passivation, doping, or integration with mechanically robust matrices, indicating that similar strategies could be adapted for GY systems.383
However, scalable and cost-effective synthesis with high crystallinity of GBMs remains fundamentally constrained by kinetic and thermodynamic limitations. Unlike GRA, which is composed entirely of sp2-hybridized carbon stabilized by strong π–π conjugation, GBMs such as GY and GDY comprise mixed sp–sp2 carbon networks with acetylenic linkages that possess higher formation energies and reduced thermodynamic stability under equilibrium conditions. First-principles calculations consistently indicate that GY allotropes are energetically less favorable than GRA, favoring the formation of sp2-dominated carbon phases and hindering the growth of extended, defect-free crystalline domains.158 Consequently, GBM synthesis is often governed by kinetic control, where irreversible C–C coupling reactions readily trap metastable, disordered, or amorphous structures unless narrowly optimized conditions are employed. The core difficulty lies in the formation of acetylenic (–C
C–) linkages, which require precise catalytic conditions and high activation energies for sp–sp2 coupling, often resulting in side reactions, chain buckling, or cross-linking that introduce defects and low crystallinity. Even recent approaches that embed GDY motifs into well-defined covalent organic framework (COF) architectures, facilitating crystalline GDY analogues, underscore that controlling the linkage distribution and framework periodicity is critical to suppress random coupling and defect formation, yet this introduces additional synthetic complexity and cost.388 Moreover, controlling the number of layers and uniform layer stacking is difficult because sp–sp2 hybridization weakens interlayer π–π stacking relative to GRA, increasing the likelihood of both stacking faults and heterogeneous domains, which, in turn, impairs the electronic and mechanical properties essential for applications. The lack of reversible error-correction mechanisms in typical irreversible polymerization pathways further limits the ability to anneal out defects during growth, as seen in many crystalline 2D polymers. Finally, large-scale synthesis is constrained by the availability of suitable precursors, catalysts, and substrates, as well as by the need to balance reaction conditions that favor network growth with those that minimize unwanted side reactions and structural disorder; this contributes to high production costs and limited reproducibility, blocking commercial adoption.85
The biocompatibility and structural flexibility of certain GY derivatives also open new pathways in biomedical applications, such as drug delivery, biosensing, and tissue engineering, as well as in environmental remediation and pollution control technologies. Moreover, the long-term stability of GY membranes under harsh chemical and thermal conditions continues to hinder commercial translation. Although GY offers precise ion sieving due to its intrinsic tunable pore size, achieving high selectivity among similarly sized metal ions remains a challenge. Moreover, one critical aspect is toxicity, as previous studies on GRA family nanomaterials have shown that factors such as lateral size, surface structure, functionalization, and aggregation influence cytotoxic effects.389 However, the toxicological assessments also remain largely unexplored, necessitating further experimental and environmental studies to ensure safe and sustainable deployment.
Looking ahead, developing advanced functionalization and doping strategies, incorporating chemical ligands or hybrid nanostructures such as metal–organic frameworks, could further improve ion selectivity and separation efficiency. The design of multifunctional GY membranes capable of simultaneous removal of multiple contaminants, including heavy metals and radioactive ions, offers a promising direction for future research. Additionally, retrofitting GY-based membranes into existing industrial separation infrastructures could accelerate their practical adoption. From a computational perspective, MD and DFT are powerful tools for exploring the unique properties of GBMs and guiding the rational design of next-generation GBMs with tailored functionalities for environmental, energy, and healthcare applications. While MD simulations enable the dynamic investigation of ion transport, water permeation, and rejection mechanisms at the nanoscale, DFT offers atomistic-level insights into adsorption energies, charge transfer, electronic structures, and interfacial interactions. Together, these complementary approaches deepen our understanding of the structure–property relationships that govern GY's separation performance, sensing, and catalytic activity. Despite this promise, several challenges remain. The high computational costs required to simulate millions of atoms over numerous time steps limited timescales that constrain the investigation of slower processes, including large-scale structural changes and sensitivity to the precision of force fields, which approximate interatomic interactions and directly impact the dependability of the computational results.390–392
In summary, GBMs represent a transformative platform with cross-disciplinary impacts, bridging nanoscience and practical technology. With sustained research efforts focused on scalable synthesis, defect control, performance optimization, and toxicity evaluation, GBMs are poised to revolutionize advanced separation, sensing, energy conversion, and biomedical systems, contributing to a sustainable and technologically advanced future.
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