The catalytic relevance of hydrothermally substituted Zn on the zeolite ZSM-5 during the methanol-to-aromatics process

Abstract

The methanol-to-aromatics (MTA) process, catalyzed by both unmodified and metal-loaded zeolite ZSM-5, offers a promising and sustainable approach for producing liquid aromatics directly from renewable feedstocks. However, traditional metal incorporation methods often result in metals being confined to the surface or pores of the zeolite. While this can enhance aromatic selectivity, it tends to negatively impact the catalyst's lifetime. To address this challenge, this study focuses on the impact of incorporating Zn into ZSM-5 using a post-synthetic hydrothermal substitution process, which differs from traditional metal impregnation methods. Our approach successfully integrates Zn directly into the zeolite framework, enhancing aromatic selectivity and extending catalyst lifetime—a counterintuitive result, as higher selectivity typically accelerates catalyst deactivation. We employed advanced characterization techniques, including operando UV-vis diffuse reflectance spectroscopy and solid-state NMR, to gain deeper insights into how the dual-cycle mechanism governs the MTA process. These findings will pave the way for developing upgraded zeolite-based catalytic systems for the valorization of C1 renewable feedstocks in aromatics production.

---

1. Introduction

The zeolite ZSM-5 catalyzed methanol-to-aromatics (MTA) process is arguably the most effective and sustainable method for producing liquid aromatics directly from renewable feedstocks, provided that methanol is sourced from carbon dioxide, biomass, or waste.^1–8 This reaction exemplifies “C1 chemistry”, where petrochemicals can be derived from C1 feedstocks like methanol.^9–11 Unfortunately, aromatics are currently sourced only from petroleum reserves.^3,7 There is an urgent need for a strategic shift to produce aromatic-based petrochemicals from renewable sources, which presents its own challenges. For instance, only 3-dimensional 10-member ring zeolites are capable of producing aromatic products because they contain intersections ideal for aromatization (via the right confinement effect)—a step that cannot be achieved using other zeolites.^3,12 Therefore, understanding the physicochemical changes in these zeolites is essential to assess their impact on aromatic selectivity, which could lead to improved or enhanced catalyst design. This aspect represents the fundamental scope of our work.

As global demand for synthetic fuel and chemicals grows, the parent reaction of MTA, i.e., the methanol-to-hydrocarbon (MTH) process, offers an effective way to produce these preferential products without relying upon fossil reserves.^13,14 Herein, aromatic compounds are indispensable raw materials in medicine, agriculture, and manufacturing, making the MTA technology promising.^3,15 While there have been a few examples of MTA demonstration plants globally,¹⁶ large-scale commercial production faces challenges due to technical issues, such as the complex mechanisms involved and rapid coke formation. These challenges make the MTA process a topic worthy of further investigation. A critical review of contemporary MTA literature reveals that much of the focus has been on improving or controlling aromatic selectivity.^1,3 Typically, transition metals that facilitate aromatization/cyclization steps, such as Zn or Ga, have been added to zeolites to enhance selectivity.^17–24 However, these metals are usually impregnated into the zeolites, with other incorporation methods remaining largely unexplored.^25–28 To address this “knowledge gap”, our project was designed to examine the impact on aromatic selectivity when Zn is introduced into the zeolite using a post-synthetic hydrothermal substitution process.

We designed this project using the acidic zeolite ZSM-5, incorporating different loadings of Zn (Scheme 1). The key difference between the metal impregnation strategy commonly used in the literature and our post-synthetic metal incorporation approach lies in the final location of the metals.^25–29 In typical impregnation methods, metallic species occupy the void spaces within the zeolite, which constitutes “through-space interaction” between redox-metallic and acidic-zeolite sites.^22,30 In contrast, our hydrothermal substitution process results in the incorporation of metals directly into the zeolite framework, resembling a “through-bond interaction” between two different active sites.^25–29 Catalytic testing of bifunctional zeolites following hydrothermal substitution of metallic sites has not appropriately been evaluated for MTH/MTA catalysis, although it has previously been tested for other zeolite-catalyzed reactions.^25–29 Moreover, the higher acidity of the zeolite promotes hydrogen transfer reactions, which enhances the selectivity for aromatics, but it also results in the formation of significant by-products, such as C₂–C₄ alkanes and coke precursors.^3,31–33 Besides the zeolite structure, controlling the dual-cycle mechanism is also a critical approach to improving aromatic selectivity.^4,34–36 The dual-cycle mechanism consists of two intra-connected alkene and arene-based cycles, which control the autocatalytic stage of the MTH/MTA process.^34–40

Scheme 1 The project design: the simplified illustration of the zeolite synthesis recipe employed in this work and its application during the MTA process.

The key to improving aromatic selectivity is to push the equilibrium of the dual cycle toward the arene-cycle, which can be achieved by optimizing Zn loading, as demonstrated in this work. Typically, increasing aromatic selectivity leads to faster catalyst deactivation, as arene-based species are precursors to coke formation.^12,15 However, we show that incorporating Zn via our hydrothermal substitution step can extend the catalyst's lifetime, highlighting the effectiveness of our synthetic approach. In addition to traditional zeolite characterization, we also employed advanced techniques like operando UV-vis diffuse reflectance (DRS) coupled with online mass spectrometry and solid-state NMR spectroscopy. This multimodal approach not only helped us evaluate the impact of Zn on the dual-cycle mechanism but also deepened our understanding of the zeolite-catalyzed MTH/MTA process.

2. Results and discussion

2.1 Physicochemical properties of zeolite catalysts

The current study includes the following three core materials: the parent and unmodified zeolite ZSM-5 and two different Zn-loaded materials, 0.19Zn_F-ZSM-5 and 0.22Zn_F-ZSM-5. Herein, the “number” and “F” represent their metallic loading (as determined by ICP) and framework positions of the metals, respectively. Their characterization results are presented in Fig. 1, Table 1, Fig. 2 and S2–S4.† As shown in Fig. 1, after the introduction of Zn by post-synthetic hydrothermal substitution, no peaks related to Zn were detected in both 0.19Zn_F-ZSM-5 and 0.22Zn_F-ZSM-5 catalysts, indicating highly dispersed Zn atoms. It is worth noting that the peak splitting can be observed in both 0.19Zn_F-ZSM-5 and 0.22Zn_F-ZSM-5 catalysts at around 2θ = 23.7° and 24.5°, which was absent in the parent ZSM-5.^25–29 This splitting phenomenon can be attributed to the substitution of metals into the MFI zeolite framework, as originally proposed and proven by the Mintova group.^25–28 Such a peak splitting aspect is a consequence of a change of the symmetry: from the orthorhombic symmetry with the space group Pnma in the parent zeolite ZSM-5 to the monoclinic symmetry with the space group P2₁/n in both Zn_F-ZSM-5 materials.^25–29 Hence, Zn enters the ZSM-5 zeolite framework through isomorphic substitution, which explains that the loading capacity of Zn has a certain limit, as narrated in the Experimental section of the ESI.† From the scanning electron microscopy (SEM) images (Fig. S2†), the parent ZSM-5 exhibits a composite of nanosized hexagonal particle morphology with ∼200 nm particle size. It can be clearly seen that the morphology of the zeolites was not influenced or altered by the introduction of Zn. Next, the textural properties of ZSM-5-based materials are shown in Table 1 and Fig. S3.† As shown in Fig. S3,† all three catalysts exhibited a type-I isotherm, indicating the microporous nature of these materials. However, all catalysts also showed a pronounced uptake at the P/P₀ = 0.9–1.0 range, which could be attributed to the aggregation of small particles, thus forming the inter-crystalline mesopores, which is in line with the SEM observations.^41–43

Fig. 1 XRD patterns of the parent ZSM-5, 0.19Zn_F-ZSM-5, and 0.22Zn_F-ZSM-5 zeolites. The peak splitting, as a result of Zn incorporation into the framework due to the hydrothermal substitution, has been emphasized on the right side.

Table 1 Summary of physicochemical properties of zeolites used in this study

Samples	S BET (cm^2)	V total (cm^3g^−1)	D average (nm)	Acidity by NH3-TPD (mmol g^−1)				Acidity by Py-IR (mmol g^−1)
				Weak	Medium	Strong	Total	C BAS	C LAS	C BAS/CLAS
Parent-ZSM-5	384	0.40	4.2	0.05	—	0.06	0.11	0.07	0.14	0.49
0.19ZnF-ZSM-5	382	0.38	4.0	0.06	0.02	0.08	0.16	0.06	0.18	0.32
0.22ZnF-ZSM-5	380	0.41	4.4	0.04	0.01	0.05	0.10	0.06	0.18	0.31

---

Fig. 2 Acidity characterization: NH₃-TPD (a) and Py-IR (b) of the parent ZSM-5, 0.19Zn_F-ZSM-5, and 0.22Zn_F-ZSM-5 zeolites (also see Table 1 for numerical values).

Afterward, the strength and concentration of acidity of the catalysts were detected by temperature-programmed desorption of ammonia (NH₃-TPD). Typically, desorption peaks of ammonia at around 100–200 °C, 200–300 °C and >300 °C were classified as weak, medium, and strong acid sites, respectively.^35,44,45 Interestingly, the parent ZSM-5 only has weak and strong acid sites, while 0.19Zn_F-ZSM-5 and 0.22Zn_F-ZSM-5 possess an additional medium acid site (Fig. 2a). This means that the introduction of Zn could influence the weak acidity and then form new types of acid sites. This aspect signifies the creation of Brønsted–Lewis acidic bifunctionality over both Zn_F-ZSM-5 materials, which is expected to impact the catalytic performance. This also indirectly confirms that Zn was indeed incorporated into the framework of the parent zeolite, rather than primarily or exclusively exchanging with H⁺ at the Brønsted acid sites, distinguishing this method from traditional impregnation.^25–28 Next, the acidity characteristic was also checked by pyridine adsorption infrared spectroscopy (Py-IR). As shown in Fig. 2b, the peaks at 1450 cm⁻¹ and 1540 cm⁻¹ are classified as Lewis and Brønsted acid sites, respectively.^46,47 It can be seen that the 0.19Zn_F-ZSM-5 and 0.22Zn_F-ZSM-5 materials show a redshift at ∼1450 cm⁻¹ compared with the parent ZSM-5, indicating that Lewis acid sites become stronger after the introduction of the Zn atom into the framework of MFI.^30,48 This aspect is consistent with the NH₃-TPD results that an additional medium acid site showed in Zn-loaded zeolites. To complement these findings, ²⁷Al magic angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy was conducted to investigate the environment of Al in all samples (Fig. S4†). It can be seen that the ∼0 ppm peak, which typically belongs to octahedral extra-framework Al species,^46,49,50 only occurs in the parent ZSM-5. However, both 0.19Zn_F-ZSM-5 and 0.22Zn_F-ZSM-5 materials led to a significant response for tetrahedral Al-peaks at ∼54.5 ppm.^46,49,50 This result implies that the Lewis acidity of Zn_F-ZSM-5 materials primarily originated from the loaded Zn and not due to the extra-framework Al species.

2.2 Catalytic performance of zeolite catalysts

In the next phase of our study, the parent and Zn-modified ZSM-5 zeolites were subjected to catalytic MTH/MTA performance evaluation. As shown in Fig. 3, the lifetime of the parent ZSM-5, 0.19Zn_F-ZSM-5 and 0.22Zn_F-ZSM-5 were around 48 h, 56 h, and 60 h, respectively. Generally, the catalyst's lifetime in the MTH reaction is typically closely associated with the rate of coke formation, predominantly composed of polyaromatic hydrocarbon precursors.⁴⁶ Interestingly, the catalysts 0.19Zn_F-ZSM-5 and 0.22Zn_F-ZSM-5 demonstrated extended catalyst lifetimes, while their aromatic selectivity increased by ∼13% and ∼18%, respectively, compared to the parent ZSM-5 catalyst. Such an increase in aromatic selectivity over Zn_F-ZSM-5 zeolites happened at the expense of other hydrocarbon products, especially longer-chain C₅₊-hydrocarbons, propylene, and butylene. For example, compared to the parent ZSM-5, both propylene and butylene selectivity of 0.22Zn_F-ZSM-5 decreased by ∼6%, indicating that the introduction of Zn inhibits the olefin cycle while promoting the aromatic cycle. Similarly, the better aromatization ability of Zn-loaded zeolite catalysts could be evidenced by the relatively lesser production of C₅₊-hydrocarbons. For instance, their selectivity decreased by ∼4–5% over both Zn_F-ZSM-5 zeolites. Next, the post-reacted zeolite materials were probed by thermogravimetric analysis (TGA) to rationalize the impact of coke and catalyst deactivation (Fig. S6†). The hard coke content for the parent ZSM-5, 0.19Zn_F-ZSM-5, and 0.22Zn_F-ZSM-5 materials were ∼11.30%, ∼4.29%, and ∼2.80%, respectively. From the aromatic distribution of all these catalysts (Fig. S5d†), it can be seen that the introduction of Zn increases the proportion of the liquid aromatic fraction (i.e., BTEX: benzene–toluene–ethylbenzene–xylene) by ∼7%, while reducing the undesired C₉₊ aromatic fraction, implying bifunctionality led to a lesser degree of alkylation of aromatics. This observation provides the necessary justification behind the lower coke content and superior catalyst lifetime of Zn-loaded materials.

Fig. 3 The MTH/MTA catalytic performance evaluation over the parent-ZSM-5, 0.19Zn_F-ZSM-5, and 0.22Zn_F-ZSM-5 zeolites: (a) methanol conversion and (b) hydrocarbon product selectivity at 400 °C under 6 h⁻¹ WHSV.

2.3 Operando studies during the reaction over zeolite catalysts

To better understand the role of framework Zn in the dual cycle mechanism, operando UV-vis diffuse reflectance spectroscopy (DRS) coupled with online mass spectroscopy (MS) was conducted to probe the hydrocarbon pool species trapped in zeolites (Fig. 4). Typically, UV-vis absorption bands around 220 nm, 280 nm, 350 nm, 430 nm, and >500 nm are generally associated with neutral benzenes, neutral methylated benzenes, less methylated benzenium ions, highly methylated benzenium ions (notably hexamethylbenzenium species), and polyarenium ions, respectively.^40,51–54 It can be seen that UV-vis bands at the >500 nm region (i.e., polyaromatic species) became pronounced after the introduction of Zn, which could be due to Zn's well-known aromatization ability.⁵¹ However, there are resemblances in the behavior of other spectral bands. Moreover, the intensity of all UV-vis bands of 0.19Zn_F-ZSM-5 and 0.22Zn_F-ZSM-5 were higher than those of the parent ZSM-5, which further confirms the superior aromatization ability of these materials. The mass profile revealed that propylene was the predominant effluent gas at the early stage of catalysis. However, with increasing the Zn loading, the peak intensity of propylene was reduced, which also indicated that the introduction of Zn promotes the arene cycle. Interestingly, the lag time (i.e., time taken by MS to detect effluent products) was longer in 0.22Zn_F-ZSM-5 than in 0.19Zn_F-ZSM-5 and the parent ZSM-5, indicating the more extended induction period. Hence, we could hypothesize that the Brønsted–Lewis acid synergy in Zn_F-ZSM-5 materials slows down the MTH/MTA process, which is eventually reflected in their longer catalyst lifetime (Fig. 3 and Table 1).

Fig. 4 The operando investigation of the MTH/MTA reaction over the parent-ZSM-5, 0.19Zn_F-ZSM-5, and 0.22Zn_F-ZSM-5 zeolites: the operando UV-vis profiles (a, c and e) and mass profiles (b, d and f), based on (a and b) parent-ZSM-5, (b and c) 0.19Zn_F-ZSM-5 and (e and f) 0.22Zn_F-ZSM-5, under 400 °C for 20 min.

2.4 Solid-state NMR studies and mechanistic outlook

To complement both the catalytic and operando studies as well as to dig deeper into the MTH/MTA process, ¹³C magic angle spinning (MAS) solid-state NMR spectroscopy has been conducted over representative post-reacted catalysts (i.e., parent ZSM-5 and 0.22Zn_F-ZSM-5) after reacting with ¹³C-enriched methanol for 20 minutes at 400 °C (Fig. 5). As shown in 1D ¹H–¹³C cross-polarization (CP) spectra of both post-reacted zeolites, the following species could be readily identified: (i) 10–45 ppm aliphatic/methyl groups, (ii) 48–60 ppm oxygenate species, including absorbed methanol (∼50 ppm), surface methoxy species (SMS: ∼55 ppm) and dimethylether (DME: ∼60 ppm), and (iii) 125–150 ppm unsaturated hydrocarbon species (i.e., olefinic/aromatics) (Fig. 5).^{12,35,38,40,51,52,55–58} It can be seen that both aliphatic and olefinic/aromatic-based peaks were relatively higher in intensity over the 0.22Zn_F-ZSM-5 material than that over the parent ZSM-5, which is in line with the higher aromatic selectivity of the 0.22Zn_F-ZSM-5 catalyst. It is worth noting that the peak intensity of the oxygenated species (like methanol or DME) was much higher over 0.22Zn_F-ZSM-5 than that over the parent ZSM-5. The unconsumed methanol/DME in the early stages of the reaction likely slows down the reaction due to the Brønsted–Lewis acid synergy in Zn_F-ZSM-5 materials. This aspect, in turn, positively impacts the catalyst's lifetime, as also corroborated during the operando characterization.

Fig. 5 1D ¹H–¹³C cross-polarization magic angle spinning (MAS) solid-state NMR spectra of molecules trapped in the post-reacted parent-ZSM-5 (in red) and 0.22Zn_F-ZSM-5 (in blue) catalysts after ¹³C-methanol conversion for 20 min at 400 °C (MAS = 10 kHz) (★ = spinning sideband).

Next, 2D ¹³C–¹³C and ¹H–¹³C correlation spectra were conducted to further investigate zeolite-trapped HCP species to rationalize the zeolite-trapped molecular scaffolds (Fig. 6). Herein, the following species were identified: (i) two different motifs of unreacted methanol [i.e., side-on (η² : η²) (●: 50.1 ppm (¹³C)/3.5 ppm (¹H)) and end-on (η¹ : η¹) (□: 52.5 ppm (¹³C))/3.5 ppm (¹H); see Fig. 6a and d], (ii) surface methoxy species [SMS, ▲: 54.9 ppm (¹³C); see Fig. 6a], (iii) dimethyl ether [DME, ■: 60.1 ppm (¹³C); see Fig. 6a], (iv) branched C₃/C₄ based paraffinic moieties [○: 20–45 ppm (¹³C)/2.0–2.5 ppm (¹H); see Fig. 6c and f] and (v) methylated benzenes/aromatics [♦: 2.3 ppm (¹H)/16–20 ppm (¹³C) ↔ 35.4 ppm (¹³C) ↔ 130–140 ppm (¹³C)/2.3 ppm (¹H); see Fig. 6b and e]. It can be seen that there is not much difference between 0.22Zn_F-ZSM-5 and the parent ZSM-5 in the type of trapped aromatic and aliphatic species. However, much difference can be observed at oxygenated species, again implying the effect of the Brønsted–Lewis acid synergy in Zn_F-ZSM-5 materials as a consequence of Zn incorporation into the zeolite framework. For instance, both side-on and end-on absorbed methanol can be detected over the 0.22Zn_F-ZSM-5 material, while only side-on methanol can be detected over the parent ZSM-5 material.

Fig. 6 2-Dimensional correlation solid-state NMR spectroscopy: (a–c) ¹³C–¹³C and (d–f) ¹³C–¹H correlations over the parent-ZSM-5 (in red) and 0.22Zn_F-ZSM-5 (in blue) zeolites after the ¹³C-methanol conversion for 20 minutes at 400 °C. The respective full-range spectra are included in the ESI† (Fig. S7–S10).

Based on all the results discussed above, a plausible mechanistic scheme is summarized in Scheme 2. Different from the traditional impregnation or ion exchange methods, our post-synthetic hydrothermal substitution method synthesized automatically dispersed Zn atoms on the zeolite framework. We also noticed that Zn loading can only be optimum and make relatively stronger weak (Lewis) acids, which in turn led to the Brønsted–Lewis acid synergy beneficial for catalysis. The impact of the bifunctional synergy has been evidenced in both traditional and advanced characterization tools used in this work, as narrated above. As a result, framework Zn was able to promote the arene cycle via consuming short olefins and cyclization of C₅₊-hydrocarbons (Fig. 2b). This consideration prompts the need to recognize that, although aromatic selectivity is often strongly correlated with the arene cycle in dual-cycle mechanisms and with the zeolite's lifetime/deactivation behavior, the conversion of aromatics into deactivating species is still highly dependent on multiple factors, including side-reactions like alkylation and C–C coupling.^1,12 For example, deactivation-friendly species like formaldehyde are likely to play a significant role in the formation of coke species.^59,60 This insight suggests the possibility that achieving both high aromatic selectivity and extended catalyst lifetime in the MTA process is counterintuitive.^59,60 One way to deal with this issue is to pause the transformation of the liquid BTX aromatic fraction to the C₉₊-aromatic fraction, which is a coke precursor.^61,62 The most intriguing mechanistic aspect of this work is that the Zn_F-ZSM-5 materials lead to superior aromatic selectivity and liquid BTEX fraction, while simultaneously extending the catalyst lifetime and reduced coke content. This counterintuitive factor is the biggest selling point of this work, as well as the synthesis recipe employed.

Scheme 2 A proposed mechanistic overview of the MTH/MTA reaction based on the experimental observation obtained in this work.

3. Conclusion

To assess the impact of framework Zn on the MTA/MTH reaction outcomes, we synthesized Zn_F-ZSM-5 materials using post-synthetic hydrothermal substitution methods. Both the Zn-modified and parent zeolites were thoroughly characterized, including advanced techniques like operando characterization and solid-state NMR spectroscopy. We found that the Zn_F-ZSM-5 materials not only achieved higher aromatic selectivity compared to the parent zeolite but also demonstrated a superior catalyst lifetime. This finding is counterintuitive, as higher aromatic selectivity typically leads to faster catalyst deactivation, which was not observed in our study. Additionally, Zn_F-ZSM-5 materials produced a higher fraction of liquid aromatics and exhibited lower coke deposition than the parent zeolite. Our multimodal characterization revealed that the optimal Zn loading resulted in a beneficial Brønsted–Lewis acid synergy within the Zn_F-ZSM-5 materials, attributed to Zn incorporation into the zeolite framework. This synergy positively influenced the catalysis, leading to improved selectivity for desired products and extended catalyst lifetime. These results emphasize the positive impact of our hydrothermal substitution-based post-synthetic zeolite modification step, leading to valuable catalytic observations and fundamental insights. We believe that this work enhances the fundamental understanding of MTH/MTA reactions over bifunctional metal/zeolite catalytic systems and will aid in the design of improved catalytic materials for the valorization of C1 feedstocks.

Data availability

The data supporting this article have been included in the manuscript and ESI.†

Author contributions

Xin Zhang: investigation, methodology, validation, formal analysis, and writing – original draft. Xinyu You: conceptualization, investigation, methodology, validation, and writing – original draft. Yunfan Wang: data curation, review & editing. Hexun Zhou: validation and formal analysis. Xue Zhou: validation and NMR analysis. Abhishek Dutta Chowdhury: conceptualization, supervision, project administration, formal analysis, writing – original draft, writing – review & editing, and funding acquisition.

Conflicts of interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This project has been financially supported by the National Natural Science Foundation of China (NSFC) (Grant No. 22350610243, 22050410276), the Fundamental Research Funds for the Central Universities (Grant No. 2042023kf0126) (China) and the start-up research grant from Wuhan University (China).

References

1. I. Yarulina, A. Dutta Chowdhury, F. Meirer, B. M. Weckhuysen and J. Gascon, Nat. Catal., 2018, 1, 398–411.
2. U. Olsbye, S. Svelle, K. P. Lillerud, Z. H. Wei, Y. Y. Chen, J. F. Li, J. G. Wang and W. B. Fan, Chem. Soc. Rev., 2015, 44, 7155–7176.
3. T. Li, T. Shoinkhorova, J. Gascon and J. Ruiz-Martinez, ACS Catal., 2021, 11, 7780–7819.
4. J. F. Haw, W. Song, D. M. Marcus and J. B. Nicholas, Acc. Chem. Res., 2003, 36, 317–326.
5. U. Olsbye, S. Svelle, M. Bjørgen, P. Beato, T. V. W. Janssens, F. Joensen, S. Bordiga and K. P. Lillerud, Angew. Chem., Int. Ed., 2012, 51, 5810–5831.
6. P. Tian, Y. Wei, M. Ye and Z. Liu, ACS Catal., 2015, 5, 1922–1938.
7. E. T. C. Vogt, G. T. Whiting, A. Dutta Chowdhury and B. M. Weckhuysen, Adv. Catal., 2015, 58, 143–314.
8. M. Yang, D. Fan, Y. Wei, P. Tian and Z. Liu, Adv. Mater., 2019, 31, 1902181.
9. Y. Liu, D. Deng and X. Bao, Chem, 2020, 6, 2497–2514.
10. Q. Zhang, J. Yu and A. Corma, Adv. Mater., 2020, 32, 1–31.
11. G. Chen, G. I. N. Waterhouse, R. Shi, J. Zhao, Z. Li, L. Z. Wu, C. H. Tung and T. Zhang, Angew. Chem., Int. Ed., 2019, 58, 17528–17551.
12. X. Zhang, X. Gong, E. Abou-Hamad, H. Zhou, X. You, J. Gascon and A. Dutta Chowdhury, Angew. Chem., Int. Ed., 2024, 63, e202411197.
13. S. Ilias and A. Bhan, ACS Catal., 2013, 3, 18–31.
14. X. Wu, Y. Wei and Z. Liu, Acc. Chem. Res., 2023, 56, 2001–2014.
15. T. Shoinkhorova, T. Cordero-Lanzac, A. Ramirez, S. H. Chung, A. Dokania, J. Ruiz-Martinez and J. Gascon, ACS Catal., 2021, 11, 3602–3613.
16. W. Qian and F. Wei, in Multiphase Reactor Engineering for Clean and Low-Carbon Energy Applications, 2017, pp. 295–311.
17. P. Gao, J. Xu, G. Qi, C. Wang, Q. Wang, Y. Zhao, Y. Zhang, N. Feng, X. Zhao, J. Li and F. Deng, ACS Catal., 2018, 8, 9809–9820.
18. L. Sun, Y. Wang, H. Chen, C. Sun, F. Meng, F. Gao and X. Wang, Catal. Today, 2018, 316, 91–98.
19. Z. Wei, L. Chen, Q. Cao, Z. Wen, Z. Zhou, Y. Xu and X. Zhu, Fuel Process. Technol., 2017, 162, 66–77.
20. T. Fu, J. Shao and Z. Li, Appl. Catal., B, 2021, 291, 120098.
21. I. Pinilla-Herrero, E. Borfecchia, J. Holzinger, U. V. Mentzel, F. Joensen, K. A. Lomachenko, S. Bordiga, C. Lamberti, G. Berlier, U. Olsbye, S. Svelle, J. Skibsted and P. Beato, J. Catal., 2018, 362, 146–163.
22. T. Xiao, J. Luo, W. Huang, L. Lu, C. Liu and Y. Pan, ACS Catal., 2024, 14, 6881–6896.
23. K. Wang, M. Dong, X. Niu, J. Li, Z. Qin, W. Fan and J. Wang, Catal. Sci. Technol., 2018, 8, 5646–5656.
24. K. Liu, T. Shoinkhorova, X. You, X. Gong, X. Zhang, S. H. Chung, J. Ruiz-Martínez, J. Gascon and A. Dutta Chowdhury, Dalton Trans., 2024, 53, 11344–11353.
25. S. V. Konnov, F. Dubray, E. B. Clatworthy, C. Kouvatas, J. P. Gilson, J. P. Dath, D. Minoux, C. Aquino, V. Valtchev, S. Moldovan, S. Koneti, N. Nesterenko and S. Mintova, Angew. Chem., Int. Ed., 2020, 59, 19553–19560.
26. I. C. Medeiros-Costa, E. Dib, F. Dubray, S. Moldovan, J. P. Gilson, J. P. Dath, N. Nesterenko, H. A. Aleksandrov, G. N. Vayssilov and S. Mintova, Inorg. Chem., 2022, 61, 1418–1425.
27. S. V. Konnov, I. C. Medeiros-Costa, H. Cruchade, F. Dubray, M. Debost, J. P. Gilson, V. Valtchev, J. P. Dath, N. Nesterenko and S. Mintova, Appl. Catal., A, 2022, 644, 118814.
28. F. Dubray, S. Moldovan, C. Kouvatas, J. Grand, C. Aquino, N. Barrier, J. P. Gilson, N. Nesterenko, D. Minoux and S. Mintova, J. Am. Chem. Soc., 2019, 141, 8689–8693.
29. P. Ma, Y. Li, H. Zhou, M. Wang, M. Zhu, Y. Han, X. Zhang, K. Cheng and A. Dutta Chowdhury, Mater. Today Chem., 2023, 33, 101745.
30. X. Niu, J. Gao, Q. Miao, M. Dong, G. Wang, W. Fan, Z. Qin and J. Wang, Microporous Mesoporous Mater., 2014, 197, 252–261.
31. S. Müller, Y. Liu, F. M. Kirchberger, M. Tonigold, M. Sanchez-Sanchez and J. A. Lercher, J. Am. Chem. Soc., 2016, 138, 15994–16003.
32. J. S. Martínez-Espín, K. De Wispelaere, T. V. W. Janssens, S. Svelle, K. P. Lillerud, P. Beato, V. Van Speybroeck and U. Olsbye, ACS Catal., 2017, 7, 5773–5780.
33. Y. Shen, T. T. Le, D. Fu, J. E. Schmidt, M. Filez, B. M. Weckhuysen and J. D. Rimer, ACS Catal., 2018, 8, 11042–11053.
34. M. Bjørgen, S. Svelle, F. Joensen, J. Nerlov, S. Kolboe, F. Bonino, L. Palumbo, S. Bordiga and U. Olsbye, J. Catal., 2007, 249, 195–207.
35. X. Zhang, H. Zhou, Y. Ye, X. You, X. Zhou, S. Jiang, K. Liu and A. Dutta Chowdhury, Inorg. Chem. Front., 2023, 10, 6632–6645.
36. S. Lin, Y. Wei and Z. Liu, Chem Catal., 2023, 3, 100597.
37. D. M. McCann, D. Lesthaeghe, P. W. Kletnieks, D. R. Guenther, M. J. Hayman, V. Van Speybroeck, M. Waroquier and J. F. Haw, Angew. Chem., Int. Ed., 2008, 47, 5179–5182.
38. H. Zhou, X. Gong, E. Abou-Hamad, Y. Ye, X. Zhang, P. Ma, J. Gascon and A. Dutta Chowdhury, Angew. Chem., Int. Ed., 2024, 63, e202318250.
39. C. Filosa, X. Gong, A. Bavykina, A. Dutta Chowdhury, J. M. R. Gallo and J. Gascon, Acc. Chem. Res., 2023, 56, 3492–3503.
40. A. Dutta Chowdhury, K. Houben, G. T. Whiting, M. Mokhtar, A. M. Asiri, S. A. Al-Thabaiti, S. N. Basahel, M. Baldus and B. M. Weckhuysen, Angew. Chem., Int. Ed., 2016, 55, 15840–15845.
41. H. Tao, H. Yang, X. Liu, J. Ren, Y. Wang and G. Lu, Chem. Eng. J., 2013, 225, 686–694.
42. H. Tao, H. Yang, Y. Zhang, J. Ren, X. Liu, Y. Wang and G. Lu, J. Mater. Chem. A, 2013, 1, 13821–13827.
43. Y. Pan, G. Chen, G. Yang, X. Chen and J. Yu, Inorg. Chem. Front., 2019, 6, 1299–1303.
44. Y. Wang, G. Wang, L. I. van der Wal, K. Cheng, Q. Zhang, K. P. de Jong and Y. Wang, Angew. Chem., Int. Ed., 2021, 60, 17735–17743.
45. X. You, X. Zhang, Y. Ye, H. Zhou, S. Jiang, X. Zhou and A. Dutta Chowdhury, Dalton Trans., 2023, 52, 14390–14399.
46. Y. Wang, Y. Gao, W. Chu, D. Zhao, F. Chen, X. Zhu, X. Li, S. Liu, S. Xie and L. Xu, J. Mater. Chem. A, 2019, 7, 7573–7580.
47. Y. Lyu, Z. Yu, Y. Yang, Y. Liu, X. Zhao, X. Liu, S. Mintova, Z. Yan and G. Zhao, J. Catal., 2019, 374, 208–216.
48. M. Liu, T. Cui, X. Guo, J. Li and C. Song, Microporous Mesoporous Mater., 2021, 312, 110696.
49. L. Rodríguez-González, F. Hermes, M. Bertmer, E. Rodríguez-Castellón, A. Jiménez-López and U. Simon, Appl. Catal., A, 2007, 328, 174–182.
50. G. T. Whiting, S. H. Chung, D. Stosic, A. Dutta Chowdhury, L. I. Van Der Wal, D. Fu, J. Zecevic, A. Travert, K. Houben, M. Baldus and B. M. Weckhuysen, ACS Catal., 2019, 9, 4792–4803.
51. Y. Ye, E. Abou-Hamad, X. Gong, T. B. Shoinkhorova, A. Dokania, J. Gascon and A. Dutta Chowdhury, Angew. Chem., Int. Ed., 2023, 62, e202303124.
52. A. Dutta Chowdhury, A. L. Paioni, K. Houben, G. T. Whiting, M. Baldus and B. M. Weckhuysen, Angew. Chem., Int. Ed., 2018, 57, 8095–8099.
53. M. J. Wulfers and F. C. Jentoft, ACS Catal., 2014, 4, 3521–3532.
54. L. Yang, T. Yan, C. Wang, W. Dai, G. Wu, M. Hunger, W. Fan, Z. Xie, N. Guan and L. Li, ACS Catal., 2019, 9, 6491–6501.
55. A. Dutta Chowdhury, K. Houben, G. T. Whiting, S. H. Chung, M. Baldus and B. M. Weckhuysen, Nat. Catal., 2018, 1, 23–31.
56. A. Ramirez, X. Gong, M. Caglayan, S. A. F. Nastase, E. Abou-Hamad, L. Gevers, L. Cavallo, A. Dutta Chowdhury and J. Gascon, Nat. Commun., 2021, 12, 5914.
57. X. Gong, A. Ramirez, E. Abou-Hamad, T. B. Shoinkhorova, M. Çağlayan, Y. Ye, W. Wang, N. Wehbe, R. Khairova, A. Dutta Chowdhury and J. Gascon, Chem Catal., 2022, 2, 2328–2345.
58. X. Gong, Y. Ye and A. Dutta Chowdhury, ACS Catal., 2022, 12, 15463–15500.
59. S. Lin, Y. Zhi, W. Zhang, X. Yuan, C. Zhang, M. Ye, S. Xu, Y. Wei and Z. Liu, Chin. J. Catal., 2023, 46, 11–27.
60. Y. Liu, F. M. Kirchberger, S. Müller, M. Eder, M. Tonigold, M. Sanchez-Sanchez and J. A. Lercher, Nat. Commun., 2019, 10, 1462.
61. M. Bjørgen, S. Akyalcin, U. Olsbye, S. Benard, S. Kolboe and S. Svelle, J. Catal., 2010, 275, 170–180.
62. J. S. Martinez-Espin, M. Mortén, T. V. W. Janssens, S. Svelle, P. Beato and U. Olsbye, Catal. Sci. Technol., 2017, 7, 2700–2716.

---

Footnotes

† Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d4cy01168f

‡ These authors contributed equally.

---