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. 2025 Sep 5;147(37):33790–33798. doi: 10.1021/jacs.5c09969

Transition-Metal-Free Aluminosilicate Small-Pore Zeolites Upgrade Methane to Light Olefins

Peipei Xiao †, Xiaomin Tang ‡, Jingyi Tan ‡,§, Kengo Nakamura †, Hiroto Toyoda †, Masato Sawada †, Yong Wang †, Hermann Gies †,∥, Anmin Zheng ⊥,‡, Toshiyuki Yokoi †,#,*
PMCID: PMC12447477  PMID: 40910450

Abstract

Upgrading methane to value-added chemicals is significant but still challenging. Well-designed catalysts are required to activate methane. Extensive efforts have been dedicated to the catalytic conversion of methane over transition-metal-containing catalysts. A simple aluminosilicate FER-type zeolite has been found to activate methane and nitrous oxide to methanol stably. To further diversify the catalytic properties, zeolites with different topologies were screened in the methane oxidation reaction. Here, we show that small-pore zeolites have unique advantages in the direct upgrading of methane to light olefins. Among them, the CHA-type zeolite (SSZ-13) exhibited an outstanding performance, with a total selectivity of 90.5% to light olefins and a CH4 conversion of 5.3% at 350 °C, accompanied by excellent regeneration. Penta-coordinated Al species as one of the active centers was figured out for methane activation and further identified as a non-framework tetra-coordinated Al species by density functional theory (DFT) calculations. The acidity of the zeolite was confirmed to influence the tandem conversion of methanol to light olefins. Our study revealed a novel possibility that transition-metal-free aluminosilicate small-pore zeolites can serve as bifunctional catalysts directly and continuously upgrade methane to light olefins via methanol as the intermediate. This approach avoided energy consumption and cumbersome operations and achieved high-efficiency and low-energy production of light olefins.

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1. Introduction

Light olefins are bulk chemicals in the industry and important petrochemical raw materials and fuels, serving a myriad of markets. , Their production currently relies on petroleum and is realized via steam cracking of hydrocarbons, fluid catalytic cracking (FCC), and dehydrogenation of paraffin. However, there is an urgent need to develop alternative and sustainable production pathways due to the depletion of crude oil and carbon neutrality. Methane is the main component of natural gas and shale gas and is currently used as a fuel, resulting in carbon dioxide emissions. , Moreover, considering that methane itself is a strong greenhouse gas, the development of effective utilization of methane as a carbon source is strongly desired. In terms of carbon recycling, upgrading methane into light olefins as bulk chemicals is a promising approach. The conversion technologies of methane into light olefins have been established by an indirect route involving multiple steps via synthesis gas or by a direct route at high temperatures via oxidative coupling of methane (OCM) or at relatively low temperatures via selective oxidative coupling of methane by photocatalysts. ,, A variety of products, including olefins and gasoline, can be produced from syngas using the well-established Fischer–Tropsch synthesis (FTS). Alternatively, syngas can be converted to methanol, which can be further processed into chemicals using technologies such as methanol-to-olefins (MTO) and methanol-to-aromatics (MTA). , However, these methods are based on a process with a high energy consumption or low efficiency. Therefore, directly converting methane to light olefins without the intermediate step of syngas production could be more economical and environmentally friendly. However, significant challenges remain due to the stable nature of methane. Despite these challenges, there has been a global surge in research efforts aimed at directly activating methane. Techniques such as OCM, nonoxidative conversion via methane dehydroaromatization to benzene (MDA), and methane conversion to olefins, aromatics, and hydrogen (MTOAH) have shown great potential. However, in addition to the prohibitively low selectivity and yield of the desired products, the high temperatures required for these reactions lead to increased energy consumption and catalyst degradation.

The direct production of methanol from methane without the intermediate step and under mild conditions is potentially more environmentally friendly and economical. However, this process is undoubtedly more challenging due to the strong C–H bond of CH4. , The strategy commonly studied involves lowering the activation energy barrier using catalysts, followed by cleavage of the C–H bond with the assistance of oxidants to produce methanol. Inspired by the methane monooxygenase, significant efforts have been dedicated to the transition-metal- or noble-metal-containing catalysts that facilitate the direct oxidation of methane to methanol. However, the stability of methane and the instability of methanol limit the reaction performance, resulting in extremely low methane conversion. − Recently, a continuous reaction route has been employed to oxidize methane directly. − With sufficient methanol and acid sites, methanol can be continuously converted. A combination of Cu-SSZ-13 and H-ZSM-5 zeolites was utilized as the bifunctional catalyst to achieve the tandem conversion of methane to methanol and, subsequently, methanol and benzene to toluene. However, only 0.4% of CH4 conversion was obtained at 1.1 MPa and 330 °C. We have also reported that Cu- or Fe-containing aluminosilicate zeolites can serve as efficient bifunctional catalysts for converting methane to light olefins at 275–350 °C. , The activity of oxidative sites, , acidity, , spatial location of the bifunctional sites, and the morphology of zeolites were found to impact subsequent tandem reactions. Moreover, the topological structure of zeolites has also been reported to influence the subsequent MTO reaction. Recently, transition-metal-free aluminosilicate zeolites have attracted attention in terms of unique catalytic capability derived from the Al atoms in specific zeolites. We reported that the transition-metal-free aluminosilicate FER-type zeolite can effectively and stably oxidize methane to methanol due to its two-dimensional (2D) channel system and unique aluminum distribution. Very recently, a similar reaction performance was reproduced over FER zeolites by Ipek and co-workers. The study confirmed the viability of employing transition-metal-free aluminosilicate zeolites as catalysts for the production of methanol from methane. Therefore, zeolites with varying topological structures warrant further investigation.

To diversify the catalytic properties, aluminosilicate zeolites with different topologies were screened in the oxidation of methane. Transition-metal-free small-pore zeolite catalysts have been found to oxidize methane to light olefins more effectively via methanol as the intermediate than medium- and large-pore zeolites at 350 °C. Through various characterization techniques and density functional theory (DFT) calculations, extra-framework penta-coordinated Al (Al V ) species were responsible for methane oxidation to methanol, and acid sites facilitated the subsequent conversion of methanol to olefins. These results provide broad development prospects for the effective utilization of methane as a resource.

2. Results and Discussion

2.1. Screening Transition-Metal-Free Zeolites for Methane Oxidation

To ensure reproducibility and applicability, commercial zeolites were applied preferentially in this study (Figures S1–S4 and Tables S1–S3). The screening tests of methane oxidation over various aluminosilicate zeolites are illustrated in Figure a,b. Light olefins (C2 =–C4 =) were the primary products over small-pore zeolites. Additionally, methanol and dimethyl ether (DME) dominated the product distribution over medium-pore 10-ring (R) 2D FER zeolite. It was more conducive to transfer substances between channels for MFI zeolite with 10 R and 3D structures, resulting in the production of both light olefins and aromatics. The formation of methanol and light olefins was severely hindered for large-pore zeolites. Based on our previous work, it was ascribed to the increased spatial distance between oxidative sites and acid sites. In addition, the pore size of zeolites influenced acid strength, as evidenced by lower desorption temperatures in the NH3-TPD curves, contributing to the lower hydrocarbon formation rate (Table S2). , The results signaled the effects of confinement, shape-selectiveness, and diffusion of zeolite structures. , A possible schematic diagram was unraveled by oxidizing methane to methanol on oxidative sites and then converting methanol to light olefins on acid sites by diffusing along the channels (Figure c). Based on the screening results, CHA zeolite was selected to further understand and improve the catalytic properties hereafter due to its outstanding performance, even compared with transition-metal-containing zeolites (Table S4).

1.

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Screening results of transition-metal-free aluminosilicate zeolite catalysts for methane oxidation with N2O. (a) Product selectivity and CH4 conversion and (b) methanol and hydrocarbon formation rate of transition-metal-free zeolite catalysts with different topological structures in the methane oxidation reaction. Reaction conditions: 100 mg catalyst, 350 °C, CH4/N2O/H2O/Ar = 10/10/2/3 mL min–1, TOS = 0.16 h, hydrocarbons formation rate r hydrocarbons = 2*­(r C2 = + r C2 0 ) + 3*­(r C3 = + r C3 0 ) + 4*­(r C4 = + r C4 0 ) + 5*­(r C5 = + r C5 0 ) + 6*r C6 . (c) Schematic diagram to depict methane oxidation to methanol on oxidative sites, followed by methanol to light olefins on acid sites.

2.2. Influences of Reaction Conditions on Catalytic Performance

The effects of reaction conditions, including reaction temperature, gas composition, cofeed of water, and catalyst amount, on the reaction performance were investigated. The product was not observed until the reaction temperature was raised to 275 °C due to the high energy barrier. Similar to the Fe- or Cu-zeolite, methanol as the main product was observed at relatively low temperatures. , Therefore, methanol was confirmed as the direct product of methane oxidation on the CHA zeolite. Light olefins became the primary products at 300–400 °C with CH4 conversion growing from 0.4 to 7.8% (Figures a and S5) and carbon deposit amount enhancing from 12.0 to 15.8% (Figure S6).

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Effects of reaction conditions on the performance and reusability tests of transition-metal-free CHA zeolites in methane oxidation with N2O. (a) Reaction temperature. Reaction conditions: 100 mg catalyst, 275–400 °C, CH4/N2O/H2O/Ar = 10/10/2/3 mL min–1, TOS = 0.16 h. (b) Water partial pressure. Reaction conditions: 100 mg catalyst, 350 °C, CH4/N2O/H2O/Ar = 10/10/x/(45–x) mL min–1 (x = 0–8), TOS = 0.16 h. (c) CH4 partial pressure. Reaction conditions: 100 mg catalyst, 350 °C, CH4/N2O/H2O/Ar = 10/10/2/y mL min–1 (y = 3–43), TOS = 0.16 h. (d) Catalyst mass. Reaction conditions: 2.5–200 mg catalyst, 350 °C, CH4/N2O/H2O/Ar = 10/10/2/3 mL min–1, TOS = 0.16 h. (e) Product distribution and CH4 conversion in the methane oxidation reaction for CHA zeolites reused several times. Reaction conditions: 350 °C, 100 mg catalyst, CH4/N2O/H2O/Ar = 10/10/2/3 mL min–1.

The role of water in the catalytic conversion of C1 molecule reactions has been extensively studied. It is generally accepted that water facilitates hydrogen transfer and aids in dissolving methanol during the oxidation of methane to methanol. Consequently, increasing the partial pressure of water can significantly enhance the yield of methanol. , In this study, the water partial pressure was adjusted by varying the flow rate of both water and the carrier gas. As illustrated in Figure b, CH4 conversion decreased from 5.3 to 3.3% with the increase of water partial pressure from 0 to 12.5 kPa due to the dealumination of CHA zeolite under high water partial pressure. The methanol formation rate exhibited an opposite trend compared with the hydrocarbon formation rate (Figure S7), signaling that the principle of water-promoting methanol formation also applied to CHA zeolite.

The partial pressure of CH4 was adjusted by altering the flow rate of Ar from 3 to 43 mL min–1. The highest CH4 partial pressure contributed to the highest CH4 conversion of 4.8% with a light olefins selectivity of 93.0% (Figures c and S8). The CH4/N2O ratios were adjusted by keeping the total flow rate unaffected. The CH4/N2O ratio did not significantly influence the product distribution due to the excessive reactants, different from Fe zeolites (Figure S9). The total flow rate was regulated by substantially increasing the amounts of reactants and carrier gas. The selectivity of light olefins was enhanced from 49 to 91% due to the improved mass transfer by fixing the partial pressure of the reactants and increasing the total flow rates (Figure S10).

As the catalyst mass increased from 2.5 to 300 mg, CH4 conversion escalated from 0.2 to 6.4%, accompanied by enhanced selectivity of C2 0–C4 0 from 0 to 55% (Figures d and S11). A longer catalyst bed was not beneficial for the production of light olefins. The effect of catalyst mass on CH4 conversion can be divided into three stages with gradually intensified mass transfer resistance (Figure S11). The stability of 50 mg of CHA zeolite with a feed of CH4/N2O/H2O/Ar = 10/10/45/0 mL min–1 was tested at 350 °C (Figure S12), suggesting that appropriate water as feed was required for the cascade reaction.

2.3. Stability and Reusability Test

The stability and reusability of CHA zeolite were evaluated under typical reaction conditions (100 mg of the catalyst, 350 °C, CH4/N2O/H2O/Ar = 10/10/2/3 mL min–1). For the fresh sample, CH4 conversion gradually decreased from 3.9 to 0.3% after 20 h of continuous reaction due to carbon deposits on the acid sites (Figure e). However, the methanol selectivity gradually increased from 0.5 to 72.8% as the carbon deposits did not weaken oxidative sites for methane oxidation to methanol. The spent catalyst was regenerated by calcination at 550 °C in air for 5 h (Figure S13). After regeneration and an additional 20 h of continuous reaction conducted twice, the reaction performance remained comparable to that of the fresh samples. Following the fourth regeneration, the initial hydrocarbon selectivity remained at 100%. However, CH4 conversion decreased to 2.6% due to the reduced acid sites derived from dealumination (Figures e and S13). The observed decrease in CH4 conversion confirmed that the second-step MTO reaction promoted the initial methane oxidation step, consistent with our recent findings. Despite the inevitable deactivation of small-pore zeolites due to carbon deposits, the CHA zeolite demonstrated excellent reusability.

2.4. Revealing the Active Sites for the Oxidation of Methane to Methanol

In our previous work, the penta-coordinated Al (Al V ) species originating from dealumination were identified as the active site on transition-metal-free FER-type zeolites in the methane oxidation to methanol reaction. The extra-framework Al species were artificially added by ion exchange or impregnation. The 27Al MAS NMR spectra revealed enhanced intensity in both Al V and hexa-coordinated Al (Al VI ) species for IE-5Al/CHA, while imp-0.5Al/CHA primarily exhibited an increase in Al VI species (Figure a and Table S5). To assess the catalytic activity in methane oxidation to methanol, the reaction was conducted at 275 °C. As illustrated in Figure b, the CH4 conversion increased after Al addition. Furthermore, to evaluate the catalytic activity in both methane to methanol and methanol to light olefins, the reaction was performed at 350 °C. CH4 conversion improved for IE-5Al/CHA (Figure S14), suggesting that both Al V and Al VI could serve as potential active sites for the conversion of methane to methanol. However, because Al2O3, which contained a high proportion of Al VI , did not exhibit activity in methane oxidation (Figure S15), Al VI species were not active sites.

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Research on active sites for converting methane to methanol. (a) 27Al MAS NMR and (b) reaction performance of CHA zeolites with supplementation of Al species at 275 °C at TOS = 0.16 h. (c) Evaluation of the reaction performance of the pristine CHA zeolite at 275 °C without or with activation, (d) comparison of the 27Al MAS NMR spectra of fresh and used samples after the reaction at 350 °C without or with activation. Reaction conditions: 100 mg catalyst, 275 °C, CH4/N2O/H2O/Ar = 10/10/2/3 mL min–1.

To better understand the formation of active Al species, the original CHA zeolite was used without calcination or activation before the reaction (Figure S16). When the reaction was conducted at 275 °C, methanol was obtained as the primary product without or with activation (Figure c). However, the product shifted from methanol to light olefins after the reaction for 2 h in the case of activation. The initial CH4 conversion was only 0.7% at 350 °C without activation (Figure S16), while it was significantly improved to 2.4% at 350 °C with activation. A comparison of 27Al MAS NMR spectra between fresh and spent CHA zeolites at 350 °C revealed the increased intensity of distorted Al (Al IV‑2 ) at 80–63 and 50–40 ppm, as well as penta-coordinated Al (EFAl V ) at 40–20 ppm (Figure d). Notably, the increased intensity with activation was greater than that without activation. Therefore, it can be concluded that the processes of calcination, activation, and reaction generated active Al species on CHA zeolite for the oxidation of methane to methanol.

2.5. Influence of Acidity

Acidity as one of the features affecting the conversion of methane to light olefins was studied. First, the quantity of active Al species and acid sites behaves like a seesaw, which was adjusted by calcination temperature (Figure S17). The acid amount decreased as the temperature rose from 550 to 850 °C (Figure a and Table S5). The intensity of the potential active Al species identified by 27Al MAS NMR spectra showed the opposite result (Figure S17). The hydrocarbon formation rate decreased as the temperature increased, primarily due to the reduced acid amount (Figures b, S18, and S19). Notably, H-CHA-850 with significantly reduced acidity obtained 166 μmol g–1 min–1 hydrocarbon formation rate, suggesting that the quantity and strength of acid sites were not the sole determinant for light olefins production. Consistent with our previous report, the spatial arrangement of oxidative sites and acid sites was also a critical factor.

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Research on active sites for converting methanol to light olefins. (a) NH3-TPD curves and (b) reaction performance of H–CHA-t. (c) NH3-TPD curves and (d) reaction performance of yNa/CHA. Reaction conditions: 100 mg catalyst, 350 °C, CH4/N2O/H2O/Ar = 10/10/2/3 mL min–1, TOS = 0.16 h, hydrocarbons formation rate r hydrocarbons = 2*­(r C2 = + r C2 0 ) + 3*­(r C3 = + r C3 0 ) + 4*­(r C4 = + r C4 0 ) + 5*­(r C5 = + r C5 0 ) + 6*r C6 .

Furthermore, the acidity was adjusted by Na exchange (Figures c and S20 and Table S5). The notably reduced strong acid content in CHA zeolite resulted in a sharp decline in both the formation rate and selectivity of light olefins (Figures d, S21, and S23). Moreover, similar to the one-pot synthesized Fe-zeolite, Na ions on the extra-framework inhibited dealumination, thereby limiting the formation of active Al species. Consequently, the methanol formation rate of H-CHA increased after 5 h of the reaction; however, it decreased for 50 and 2500Na/CHA (Figure S21). The 27Al MAS NMR spectra of the fresh and spent H–CHA and 2500Na/CHA zeolites confirmed the role of Na cations in preventing dealumination (Figure S21). Schematic diagrams illustrating the effects of acidity on light olefin formation through dealumination and the introduction of Na ions are provided (Figure S22).

2.6. Mechanistic Studies

N2O adsorption Fourier-transform infrared spectroscopy (FTIR) was conducted at 25 °C to elucidate the oxidant binding to the oxidative site. Two bands corresponding to Al-ONN at 2248 and 2229 cm–1 were observed (Figure S24), being consistent with FER and MIL-100­(Fe) catalysts. , Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of methane oxidation over CHA zeolite was performed to provide insight into the reaction mechanism. As shown in Figure a, the peak at 2978 cm–1, assigned to the CH3O species, was gradually intensified after cofeeding of CH4, N2O, and Ar over CHA zeolite at 250 °C as time increases from 2 to 20 min. Subsequently, the weak peak at 2866 cm–1, assigned to CH3OH, was detected. − The results confirmed the intermediate of methoxy in the oxidation of methane to methanol (Figure S25). , When the temperature was changed from 250 to 500 °C (Figure b), the intensity of peaks at 2978 and 2866 cm–1 strengthened first and then reduced. However, the peaks at 2918 cm–1 ascribed to CH3OCH3, 2340 and 2362 cm–1 assigned to CO2, and 2144 and 2100 cm–1 assigned to CO were strengthened. − The results indicated that CH3OH was readily converted to DME and overoxidized to CO and CO2 at high temperatures (Figure S25). Unlike the methane oxidation to light olefins observed on CHA zeolite in Figures –, light olefins were not observed in the DRIFTS experiment due to the limited mass transfer between bifunctional sites.

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In situ DRIFTS spectra of CHA zeolite after cofeeding of CH4 (5 mL/min), N2O (5 mL/min), and Ar (500 mL/min) at (a) 250 °C maintained for 0–20 min and (b) 250–500 °C for 20 min after pretreatment at 500 °C for 1 h. (c) Schematics depicting the possible transformation of Al species. (d) Free energy diagrams for the oxidation of methane to methanol on the active EFAl site at 350 °C. The corresponding structures are shown in Figure S29. (e) A schematic representation of the direct oxidation of methane to light olefins via methanol as the intermediate, involving the formation of active species, using extra-framework penta-coordinated aluminum [Al­(OH)2(H2O)3]+ as an example, along with dehydration, N2O activation, CH4 adsorption, methanol formation, the transport of methanol to Brønsted acid sites, and its conversion to light olefins.

To shed light on the conversion of methane to light olefins on Al species, the particular Al species was examined. The transformation of framework tetra-coordinated Al (Al IV‑1 ) to distorted framework Al (Al IV‑2 ), subsequently to extra-framework Al (EFAl), which included tricoordinated Al (EFAl III ), tetra-coordinated Al (EFAl IV ), penta-coordinated Al (EFAl V ), and hexa-coordinated Al (EFA VI ), is depicted in Figure c. ,− Among them, EFAl III was referred to as ‘‘invisible Al” due to its undetectability in the 27Al MAS NMR spectrum, and EFAl IV was hypothetical here. Additionally, among various types of extra-framework Al species, such as [AlO]+, [Al­(OH)2]+, [AlOH]2+, AlO­(OH), and Al­(OH)3 species, it was noted that the terminal oxo ligands and highly cationic species were unstable. This instability left cationic [Al­(OH)2]+ and neutral Al­(OH)3 species as the most possible EFAl species in CHA zeolite. Although both positively charged and neutral extra-framework Al species were considered, neutral Al­(OH)3 was inactive (Figure S26). Therefore, only positively charged EFAl V coordinated with water molecules or framework oxygen atoms was studied in this work (Figure S27). The most stable [Al­(OH)2(H2O)3]+ was selected to perform ab initio molecular dynamics (AIMD) simulations to verify its stability in the CHA zeolite at 25 °C. It was observed that the Al–O distances varied within 2.5 Å for the majority of the AIMD simulation (Figure S28), indicating that [Al­(OH)2(H2O)3]+ maintained penta-coordination. Notably, the direct oxidation reaction of methane to olefins was conducted at 350 °C; thus, performing the AIMD simulation at the same temperature was essential. However, the Al–O1 distance suddenly increased to over 3.0 Å after 1.2 ps at 350 °C, resulting in the loss of one H2O molecule from [Al­(OH)2(H2O)3]+, which then was transformed into EFAl IV [Al­(OH)2(H2O)2]+. Consequently, the DFT calculation of the reaction pathway for oxidation of methane to methanol was based on EFAl IV ([Al­(OH)2(H2O)2]+) in the CHA zeolite (Figure d). N2O activated [Al­(OH)2(H2O)2]+ by inserting an active oxygen atom from N2O into one of the hydroxyl groups of EFAl IV , forming [Al­(OOH)­(OH)­(H2O)2]+ with a reaction barrier of 46.3 kcal/mol. Subsequently, CH4 was adsorbed onto the active oxygen site with an adsorption energy of 7.1 kcal/mol, leading to the rupture of the C–H bonds in CH4. The active oxygen was then incorporated to form a hydroxyl group with a reaction barrier of 20.5 kcal/mol (Figures d and S29). Thereafter, CH3OH was desorbed, and active Al species [Al­(OH)2(H2O)2]+ was regenerated, entering the next cycle. By the way, there were no free radicals found in the reaction pathway, and hence, the free radical pathway was excluded. The DFT simulated pathway illustrated the thermodynamic and kinetic feasibility of the proposed mechanism of methanol formation on CHA zeolite. Finally, two cycles involving the oxidation of methane to methanol on the active Al species derived from EFAl V ([Al­(OH)2(H2O)3]+) and the conversion of methanol to light olefins on acid sites are presented in Figure e. Regarding the MTO reaction, the pathway was expected to follow an aromatic-based cycle because C2 =–C3 = were primarily observed in both single and tandem MTO reactions (Figure S30). ,

3. Conclusions

Transition-metal-free aluminosilicate small-pore zeolites were found to effectively convert methane to light olefins via methanol as the intermediate. The potential impacts of reaction conditions on catalytic performance were investigated by taking CHA zeolite as an example. CHA zeolite achieved outstanding performance with a total selectivity to light olefins of 90.5% and a CH4 conversion of 5.3% at 350 °C, accompanied by excellent regeneration. The extra-framework penta-coordinated Al (EFAl V ) has been identified by 27Al MAS NMR as one of the active sites for the oxidation of methane to methanol. DFT calculations confirmed that the detected EFAl V [Al­(OH)2(H2O)3]+ at 25 °C would convert to EFAl IV [Al­(OH)2(H2O)2]+ at 350 °C via dehydration. The acid site was confirmed as the active site for the subsequent conversion of methanol to light olefins. Combining experimental data and DFT calculations, a possible reaction mechanism was proposed. Our study revealed a novel possibility that transition-metal-free small-pore zeolites can serve as bifunctional catalysts to directly and continuously convert methane to light olefins. This approach avoided the energy consumption associated with the direct route and the cumbersome operations required by the indirect syngas route, achieving high-efficiency and low-energy production of light olefins.

Supplementary Material

ja5c09969_si_001.pdf (4.8MB, pdf)

Acknowledgments

This work was supported by the JSPS KAKENHI Grant-in-Aid for Scientific Research (B) (No. 21H01714) and JSPS KAKENHI Grant-in-Aid for Scientific Research (S) (No. 23H05454), the Natural Science Foundation of Hubei Province (2025AFA008), and the Natural Science Foundation of Wuhan (2024040701010058).

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.5c09969.

  • Experimental details, methods, characterization results of XRD patterns, SEM images, N2 adsorption and desorption, NH3-TPD spectra, TG-DTA results of the spent samples, reaction performance of other catalysts, and DFT calculations (PDF)

¶.

P.X. and M.T. contributed equally to this work.

The authors declare no competing financial interest.

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