Themed collection Journal of Materials Chemistry A HOT Papers
Emerging electrochemical humidity sensors for zero power consumption and self-powered humidity detection: a perspective
This perspective summarizes recent advances in electrochemical humidity sensors and mainly focuses on three aspects: working principles; humidity sensing and power generation performances; self-powered humidity detection system.
J. Mater. Chem. A, 2024,12, 14975-14985
https://doi.org/10.1039/D3TA06283J
Hydrogen generation from atmospheric water
Green hydrogen, produced by water splitting with renewables, faces water scarcity issues. Atmospheric moisture, a stable source, offers an alternative. This article reviews technologies and challenges of using atmospheric water for H2 production.
J. Mater. Chem. A, 2024,12, 12381-12396
https://doi.org/10.1039/D4TA00848K
CO2-tolerant perovskite cathodes for enhanced solid oxide fuel cells: advancements, challenges, and strategic perspectives
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA02455A
Recent advances in scanning electrochemical microscopy for probing the sites in electrocatalysts
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA01292E
Prospects of polymer coatings for all solid-state and emerging Li-ion batteries
We summarize the influence of polymer coatings on cathode particles for electrochemical energy storage applications. We report on the effect of different polymer types, their properties, and their influence on thermo-electro-chemical behavior.
J. Mater. Chem. A, 2024,12, 14186-14205
https://doi.org/10.1039/D4TA01061B
Review of carbon-support-free platinum and non-platinum catalysts for polymer electrolyte fuel cells: Will they feature in future vehicles?
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA02664K
Carbon-based double-metal-site catalysts: advances in synthesis and energy applications
Dual-metal site catalysts embedded in a carbon matrix (referred to as DMSCs) are gaining significant interest in sustainable energy research.
J. Mater. Chem. A, 2024,12, 11749-11770
https://doi.org/10.1039/D4TA00727A
Structure–property–performance relationship of vanadium- and manganese-based metal–organic frameworks and their derivatives for energy storage and conversion applications
The current review discusses on vanadium- and manganese-based metal–organic frameworks and their derivatives for energy storage and conversion applications along with the potential future advancements in these fields.
J. Mater. Chem. A, 2024,12, 11149-11175
https://doi.org/10.1039/D4TA00736K
Advances in the direct electro-conversion of captured CO2 into valuable products
A comprehensive review of direct captured CO2 electro-conversion technology, a promising Carbon Capture and Utilization (CCU) technology that can achieve both techno-economic and environmental viability.
J. Mater. Chem. A, 2024,12, 10597-10613
https://doi.org/10.1039/D4TA01178C
A review of noble metal-free high entropy alloys for water splitting applications
Nano-sized high entropy alloy (HEA) catalysts have attracted much attention as extraordinary electrocatalysts in water-splitting applications, i.e., the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).
J. Mater. Chem. A, 2024,12, 9933-9961
https://doi.org/10.1039/D4TA00690A
Doping engineering of phosphorus-based polyanion-type cathodes for sodium storage: a review
This review addresses four key factors and underlying mechanisms of doping engineering from crystal-field, molecular orbital, and ligand-field theory.
J. Mater. Chem. A, 2024,12, 9268-9295
https://doi.org/10.1039/D4TA00652F
Metal/covalent–organic framework based thin film nanocomposite membranes for advanced separations
Metal/covalent organic frameworks (MOFs/COFs), with orderly aligned pores and adjustable pore characteristics, offer advantages over traditional fillers in constructing thin film nanocomposite (TFN) membranes for task-specific separations.
J. Mater. Chem. A, 2024,12, 7975-8013
https://doi.org/10.1039/D4TA00578C
Exploring the mechanisms of magnetic fields in supercapacitors: material classification, material nanostructures, and electrochemical properties
The review illustrates that the magnetic field effect can promote the generation of different nanostructures in material synthesis, achieve the transition from 1D to 2D and 3D structures in material assembly and improve the energy density of supercapacitor by the direct and indirect roles.
J. Mater. Chem. A, 2024,12, 6165-6189
https://doi.org/10.1039/D3TA07658J
Recent advances on metal–organic frameworks for deep purification of olefins
The efficient removal of trace impurities is significant for the production of high-purity olefins. This review summarizes the latest advancements in the deep purification of ethylene and propylene using MOF materials.
J. Mater. Chem. A, 2024,12, 5563-5580
https://doi.org/10.1039/D4TA00330F
Chemical pre-lithiation of LiMn2O4 balances the low first cycle efficiency of silicon anodes
Prelithiation of LiMn2O4 balances the low first cycle efficiency of silicon anodes for improvements in energy density and prospective cell chemistry enabled by naturally abundant elements.
J. Mater. Chem. A, 2024,12, 14354-14359
https://doi.org/10.1039/D4TA02544J
Tailoring bismuth defects in Bi2WO6 nanosheets for photocatalytic C–H activation
Tailoring the bismuth defects in ultrathin Bi2WO6 nanosheets can efficiently activate the C–H bond in toluene to produce benzaldehyde under light irradiation.
J. Mater. Chem. A, 2024,12, 11841-11847
https://doi.org/10.1039/D4TA01573H
Novel heat storage ionomer binder for thermal management of Li-ion batteries
A novel heat storage ionomer binder with highly efficient heat-storage ability is proposed to function as an internal temperature conditioner, which allows the battery to function steadily over a wider temperature range.
J. Mater. Chem. A, 2024,12, 7508-7514
https://doi.org/10.1039/D3TA07490K
Adsorptive molecular sieving of aromatic hydrocarbons over cyclic aliphatic hydrocarbons via an intrinsic/extrinsic approach
An efficient adsorptive molecular sieving strategy to separate aromatic and cyclic aliphatic hydrocarbons via an intrinsic/extrinsic approach.
J. Mater. Chem. A, 2024,12, 6875-6879
https://doi.org/10.1039/D3TA06602A
Three-dimensional porous NiCoP foam enabled high-performance overall seawater splitting at high current density
Three-dimensional porous NiCoP foam supported on Ni foam is a superb bifunctional electrocatalyst for overall seawater splitting, attaining a large current density of 1000 mA cm−2 at a low cell voltage of 1.97 V with robust stability over 300 hours.
J. Mater. Chem. A, 2024,12, 2680-2684
https://doi.org/10.1039/D3TA07898A
Ultrahigh energy storage capacities in high-entropy relaxor ferroelectrics
This study shows that entropy engineering can enhance the energy-storage performance of lead-free BNT-based dielectrics, achieving a recoverable energy density of 11.24 J cm−3 and 88.3% efficiency, with excellent stability and rapid discharge.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA03637A
Engineering semiconductor quantum dots for co-upcycling of CO2 and biomass-derived alcohol
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA01996B
Size effect of nickel from nanoparticles to clusters to single atoms for electrochemical CO2 reduction
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA03404J
Lewis functional nanodiamonds for efficient metal-free photocatalytic CO2 reduction
Advantages and disadvantages of amino- and carboxyl-modified nanodiamond (ND) for photocatalytic CO2 reduction.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02877E
In situ switchable nanofiber films based on photoselective asymmetric assembly towards year-round energy saving
An in situ switchable photoselective polymer film, assembled from asymmetric optical nanofibers, achieves high-threshold power regulation through elimination and restoration of scattering interfaces, facilitating a wide range of temperature control.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA03558E
In Situ Analysis of Gas Dependent Redistribution Kinetics in Bimetallic Au-Pd Nanoparticles
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA03030C
Low-temperature suitability of flexible photo-rechargeable devices integrated with hydrogel-based lithium-ion batteries and perovskite solar cells
The flexible photo-rechargeable device with an OEE of 12.88% displays good low-temperature suitability and safety without overcharge-induced thermal runaway.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA03076A
Controlling the steepness of gate-opening behavior on elastic layer-structured metal–organic framework-11 via solvent-mediated phase transformation
The phase of the precursor of ELM-11 affects the steepness of its gate-opening behavior, and this phase can be controlled by solvent-mediated phase transformation.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02068E
Achieving long-lived photogenerated holes in ZnIn2S4 loaded with CoOx clusters for enhanced photocatalytic pure water splitting
Ultra-small CoOx clusters efficiently capture holes and prolong the lifetime of trapped holes, as well as boost surface water oxidation, thus remarkably improving the photocatalytic pure water splitting performance of ZnIn2S4.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02620A
Self-Powered VO2 Phase Transition Based on Triboelectric Nanogenerator
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA03773A
Reactivity and Durability of TiO2 Photoanodes with Dominant High-Energy (211) Facets
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA03737E
Iron single-atom anchored N-doped carbon: an efficient catalyst for one-pot, scaled-up pentazolate synthesis
An efficient and recyclable iron single-atom catalyst with FeN4 sites has been fabricated, which can facilitate the formation of an Fe(IV)O intermediate and achieve scaled-up pentazolate synthesis via a three-step, one-pot process.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA03312D
Probing metal/high-entropy perovskite heterointerfaces for efficient and sustainable CO2 electroreduction
A novel high-entropy Sr2Fe0.4V0.4Mo0.4Ni0.4Ti0.6O6−δ (SFVMNT) perovskite, coated with in situ exsolved NiFe alloy nanoparticles, is proposed as a promising cathode material for solid electrolysis cells for CO2 electrolysis.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02372B
Balancing the triple conductivity of zinc-doped cathodes for proton-conducting solid oxide fuel cells
The Zn-doped BCF36 cathode boosts proton conductivity, lowers hydration energy and achieves a peak power density of 998.6 mW cm−2 at 600 °C with a polarization resistance of 0.151 Ω cm2 for a single cell with the BCFZ10 cathode.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02584A
Ultrathin NiO nanosheets anchored to a nitrogen-doped dodecahedral carbon framework for aqueous potassium-ion hybrid capacitors
The hierarchical and interconnected architecture of NiO/N-HPC promotes efficient electrolyte penetration, shortens ion transport path, and accelerates reaction kinetics, leading to a high-performance aqueous potassium-ion hybrid capacitor.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA01608D
Atomically ordered Ir3Ti intermetallics for pH-universal overall water splitting
Atomically ordered Ir3Ti intermetallics on carbon nanotubes exhibit remarkable performance for pH-universal overall water splitting.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02304H
Synthesis of Hofmann-based metal–organic frameworks incorporating a bis-pyrazole linker for various gas separations
We report the synthesis of two novel Hofmann-type metal–organic frameworks, [Co(H2mdp)(Ni(CN)4)] and [Fe(H2mdp)(Ni(CN)4)], using a pyrazole based organic linker. Both materials show good selectivity for C2H2 and C3H6 for several gas separations.
J. Mater. Chem. A, 2024,12, 15106-15114
https://doi.org/10.1039/D4TA00507D
Auto-oxidation of redox electrodes for the selective recovery of platinum group metals
Redox-electrodes are designed to selectively bind platinum group metals by auto-oxidation, and release them electrochemically. The platform can efficiently recover PGMs from catalytic converter leachates, and contribute to energy-efficient technologies for materials recycling.
J. Mater. Chem. A, 2024,12, 15006-15018
https://doi.org/10.1039/D4TA01384K
Enhancing the healability and degradability of epoxy via synergetic steric and electron-withdrawing effects for green electrical packaging
Synergetic steric and electron-withdrawing effects enable the fabrication of healable and degradable green electrical packaging with robust thermal, mechanical and insulating performance.
J. Mater. Chem. A, 2024,12, 14991-15005
https://doi.org/10.1039/D4TA02187H
Unlocking the efficiency of nonaqueous Li–air batteries through the synergistic effect of dual metal site catalysts: an interpretable machine learning approach
Screening transition metal combinations in dual metal site catalysts (DMSCs) for Li–air battery applications using supervised machine learning.
J. Mater. Chem. A, 2024,12, 15115-15126
https://doi.org/10.1039/D4TA01312C
High-efficiency ultrathin flexible organic solar cells with a bilayer hole transport layer
We have successfully demonstrated ultrathin flexible organic solar cells (with a total thickness of less than 1.5 μm) based on a MoO3/PEDOT:PSS bilayer HTL, achieving a PCE of 17.0% and a power-per-weight ratio of 39.3 W g−1.
J. Mater. Chem. A, 2024,12, 15099-15105
https://doi.org/10.1039/D4TA01679C
Photothermal conversion-enabled temperature modulation for the growth of complex polymorphic architectures of calcium carbonate
Stepwise temperature modulation was realized by the photothermal conversion process, which enabled the growth of complex architectures of CaCO3 that are composed of multiple polymorphic phases.
J. Mater. Chem. A, 2024,12, 15090-15098
https://doi.org/10.1039/D4TA00802B
Modulating the localized electronic distribution of Cu species during reconstruction for enhanced electrochemical CO2 reduction to C2+ products
ZrO2 stabilized Cu+ can optimize *CO adsorption and promote the following C–C coupling to achieve 70+% FEC2+ in a wide potential range.
J. Mater. Chem. A, 2024,12, 15082-15089
https://doi.org/10.1039/D4TA01184H
Thermomechanical properties of metal–organic framework HKUST-1 crystals
Based on the in situ compression tests at elevated temperatures, very different mechanical behaviours are observed in HKUST-1 crystals at different temperatures.
J. Mater. Chem. A, 2024,12, 15071-15081
https://doi.org/10.1039/D3TA08059E
Determining shunt resistances via modeling the photovoltaic performance of organic solar cells
The thermal vibration of molecules is markedly enhanced upon illumination (photoexcitation), leading to an increase in the (vibrational) free volume of photoactive layer and thereby markedly decreasing shunt resistance of device.
J. Mater. Chem. A, 2024,12, 15063-15070
https://doi.org/10.1039/D3TA08029C
Design of grid-like triple-carbon matrix confined ultrafine CoTe2 nanocrystals toward durable and fast potassium storage
Nitrogen-doped carbon grid-confined CoTe2 was synthesized through precise structural design. Benefiting from the effects of nitrogen anchoring and triple-carbon confinement, the CoTe2@T-NC electrode exhibits excellent electrochemical performance.
J. Mater. Chem. A, 2024,12, 15044-15054
https://doi.org/10.1039/D3TA07553B
Visible ozone detection and removal in two-dimensional Mn(II)-based metal–organic frameworks
Highly stable and hydrophobic two-dimensional Mn(II)-based MOFs effectively detect and remove trace O3 with discernible color change as the response.
J. Mater. Chem. A, 2024,12, 15055-15062
https://doi.org/10.1039/D3TA07938D
Regulating the thermoelectric power factor of donor–acceptor copolymers by heavy chalcogen substitution: a first-principles study
Te substitution of sulfur (S) in PzDPP-based donor–acceptor copolymers enhances n-type power factor, while Se boosts both n-type and p-type power factors. Heavy chalcogen doping strategy shows promise for improving thermoelectric properties.
J. Mater. Chem. A, 2024,12, 15036-15043
https://doi.org/10.1039/D3TA07199E
Modulating the porosity of N-doped carbon materials for enhanced CO2 capture and methane uptake
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA03273J
Elucidating Synergistic Mechanisms of Anion–Cation Electrolyte Additive for Ultra–Stable Zinc Metal Anodes
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA03414G
Analysis of the mechanism for enhanced crystalline quality of wide-bandgap Cu(In,Ga)Se2 films by pre-deposited Ag precursor
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA02513J
Over 29%-efficient, stable n-i-p monolithic perovskite/silicon tandem solar cells based on double-sided poly-Si/SiO2 passivating contact silicon cells
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA03396E
All-inorganic Sb2S3-based two-terminal tandem solar cells enable over 10.9% efficiency employing a concise interconnection layer
Sb2S3-based two terminal tandem solar cells (2T-TSCs) are reported for the first time with the assistance of lead sulfide quantum dot rear cells. The PCE of the champion TSC reaches 10.92%. Our work opens the door for Sb2S3 based 2T-TSCs.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA01881H
Biotopologically structured composite materials for low temperature energy storage
A biotopologically structured configuration constructed by an energy-saving electrodeposition method for low-temperature supercapacitors.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02625J
Advancing anode-less lithium metal batteries: ZnF2 modification and in situ structural regulation for enhanced performance
A novel LiF@LiZn10/Li composite foil was developed as an effective anode for lithium metal batteries. The uniform lithiophilic substrate and the LiF-rich SEI optimize Li+ deposition.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02431A
Nickel–cobalt oxide nanoparticles as superior electrocatalysts for enhanced coupling hydrogen evolution and selective ethanol oxidation reaction
The selective oxidation of organic small molecules not only promotes cathodic hydrogen production, but also acts as an alternative reaction to the anodic oxygen evolution reaction of electrolytic water, producing value-added products at the anode.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA03259D
In-Situ Exfoliation of Copper-Based Metal−Organic Framework for Boosting Synergistic Photoactivation of Inert C(sp3)−H Bonds and Oxygen
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA03355H
Regulating the selectivity through ionomer–catalyst interactions for high-efficiency electrocatalytic CO2 reduction
The surface morphology and microenvironment of GDEs could be altered through the addition of ionomers to electrodes. It was crucial to consider the potential interactions between the ionomer and the catalyst for better performance.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02905D
Spacer-engineering construction of continuous proton transport networks for cardo poly(biphenyl indole) high-temperature proton exchange membranes
Poly(biphenyl indole)-based membranes are designed for investigating the effect of side-chain engineering on the mechanism of manipulating proton transport.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02111H
Harnessing the power of thermoplastic elastomer-derived ordered mesoporous carbons through functionalization
This work demonstrates a series of functionalization methods to enhance the utility of thermoplastic-elastomer derived ordered mesoporous carbons, including chemical activation, heteroatom doping, and the introduction of nanoparticles.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02629B
Multiphase artificial interphase layer enabled long-life and dendrite-free sodium metal batteries
A multiphase artificial interphase layer can induce homogeneous deposition of Na+ and promote rapid transport of Na+. Therefore, the BiCl3-Na anode achieves uniform dendrite-free deposition and improves electrochemical performance.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02925A
Tungstic acid integrated metal–organic frameworks for efficient oxygen evolution reaction
Mimicking the isolated and encapsulated active manganese sites within proteins in nature through the integration of NiFe sites and tungstic acid nanoparticles in an ordered open framework in an isolated manner.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02924K
Tuning the surface charge and pore size in IPN arrested ‘covalent organic nanostructures’ through in situ exchangeable bonds for removal of persistent contaminants
J. Mater. Chem. A, 2024, Accepted Manuscript
https://doi.org/10.1039/D4TA03171G
Defect engineering and morphology adjustment assist NH4V4O10 to be a high-performance aqueous zinc ion battery cathode
The ultrathin size of SNVO with oxygen vacancies and more active sites improved the diffusion ability of Zn2+ ions. SNVO exhibits excellent cycle stability, retaining 94.6% of its capacity after 1000 cycles at 10 A g−1.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA02996H
Manipulation of Cs0.1FA0.9PbI3 crystallization behavior towards efficient carbon-based printable mesoscopic perovskite solar cells
High-efficiency MPSCs with a PCE of 18.06% were prepared by introducing PACl to manipulate perovskite crystallization in a triple-mesoporous structure.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA01254B
From pollution to energy storage: leveraging hydrogen sulfide with SU-101 cathodes in lithium–sulfur batteries
Our approach revalorizes H2S captured by the SU-101 MOF as a cathode material in lithium–sulfur batteries.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA03620D
Microstructural and electron framework-engineered 3D NiSeP-integrated CuFe composites as trifunctional electrocatalysts for sensing and urea-assisted water-splitting applications
Catalytically dynamic NSP-CF@NCW electrode engineered by strategic integration of 3D Se and P-fused NSP microflakes with CF cubes docked NCW was studied as a trifunctional electrocatalyst for urea sensing and urea-assisted water splitting.
J. Mater. Chem. A, 2024, Advance Article
https://doi.org/10.1039/D4TA01919A
Construction of NiCo-metaphosphate/hydroxide with synergistic heterostructure for sustainable biomass electro-oxidation
A heterostructured NiCo-metaphosphate/hydroxide catalyst (NiCoPi/Oi) exhibits excellent activity towards electrooxidation of 2,5-bis(hydroxymethyl)furan (BHMFOR), enabling sustainable production of 2,5-furandicarboxylic acid (FDCA).
J. Mater. Chem. A, 2024,12, 14491-14500
https://doi.org/10.1039/D4TA02046D
Constructing a robust artificial solid electrolyte interphase with a metal–organic framework for a stable Li metal anode
The metal–organic frameworks (MOFs) coating layer can promote homogeneous Li deposition.
J. Mater. Chem. A, 2024,12, 14408-14418
https://doi.org/10.1039/D4TA02158D
A novel topological indium–organic framework for reversible ammonia uptake under mild conditions and catalysis
An unprecedented trinodal 3,3,4-connected 3D MOF, [In8(μ2-OH)6(μ2-H2O)3L6Cl6]·5DMF·4H2O (L = 2,2′-dimethylbiphenyl-4,4′-dicarboxylate), has been built to show an NH3 uptake of 10.4 mmol g−1 at 273 K with the regeneration temperature of 60 °C.
J. Mater. Chem. A, 2024,12, 14501-14507
https://doi.org/10.1039/D4TA02447H
To what extent do anions affect the electrodeposition of Zn?
Achieving reversible zinc deposition/stripping necessitates careful optimization of the electrolyte composition. This study offers detailed insights into the impact of various anionic species (chloride, sulfate, perchlorate) on this process.
J. Mater. Chem. A, 2024,12, 14456-14466
https://doi.org/10.1039/D4TA01466A
About this collection
This on-going web collection features all the articles published in Journal of Materials Chemistry A in 2024 marked as HOT, as recommended by referees. Congratulations to all the authors whose articles are featured!