CHEMICAL SCIENCE

The new catalyst facilitates methane dry reforming to syngas


The team of Associate Professor Wang Yishuang and Professor Chen Mingqiang of the School of Chemical Engineering of Anhui University of Science and Technology used attapulgite natural clay material as silicon source to prepare a zeolite-encapsulated nickel-cobalt alloy catalyst with MFI topology, and found that this material can efficiently catalyze methane dry reforming to prepare syngas. The relevant research results were published in Applied Catalysis B: Environment, and the first author of the paper was doctoral student Liang Defang.

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Schematic diagram of mineset-based MFI zeolite encapsulated Ni-Co alloy catalyzed methane dry reforming to prepare syngas Courtesy of Anhui University of Science and Technology

Methane dry reforming can convert methane and carbon dioxide two greenhouse gases into syngas, and then into high-quality fuels and platform chemicals such as methanol and long-chain hydrocarbons, which is of great significance to alleviate the shortage of liquid fuels in China and help the “dual carbon” goal.

However, the methane dry reforming high-temperature reaction system is prone to the rapid inactivation of nickel-based catalysts due to sintering of active components and carbon deposition encapsulation. Therefore, the development of catalysts with high activity and stability is a key challenge.

In this work, Chen Mingqiang’s team used attapulgite natural clay as the silicon source and successfully prepared MFI topology zeolite encapsulated nickel-cobalt alloy catalyst by structural remodeling.

“The results show that the zeolite encapsulation layer is conducive to the formation of stable and defect-rich nickel-cobalt alloy structure, and the nickel-cobalt alloy structure promotes the formation of electron-rich Ni metal bits, which in turn significantly improves the ability of methane-carbon-hydrogen bond breakage. In addition, the synergistic effect of alkaline and metal sites on the surface of the zeolite layer improves the adsorption/activation of carbon dioxide molecules and their conversion to carbon monoxide by their interaction with carbon deposition precursors, thereby prolonging the service life of the catalyst while still efficiently catalyzing methane dry reforming. Wang Yishuang said.

In addition, the team members used cutting-edge technologies such as in-situ diffuse reflection to further reveal the mechanism of carbon deposition removal in the methane dry reforming process by analyzing the adsorption activation process of reactant molecules and intermediates.

Wang Yishuang said, “Clay materials such as attapulgite have the advantages of green economy, high structural stability, are natural silicon aluminum sources, and are also excellent carriers for methane dry reforming catalysts, but there is still little research on clay-based materials in this field.” Therefore, the Ni-clay-based composites prepared in this study provide an optimization strategy for improving the catalytic performance of methane dry reforming catalysts, and expand the application of clay-based materials in the fields of catalytic methane dry reforming and the preparation of syngas from low-concentration coalbed methane. ”

The reviewers believe that “in this paper, a zeolite encapsulation layer with specific micro-medial composite pores is prepared by using attapulgite instead of commercial silicon sources, which reduces the cost of zeolite synthesis, and the unique composite pores can effectively stabilize the alloy site through the pore limit without affecting the close contact between the reactants/intermediates and the encapsulation alloy site.” This is an innovative breakthrough in the design and optimization strategy of methane dry reforming catalysts. (Source: Wang Min, China Science Daily)

Related Paper Information:https://doi.org/10.1016/j.apcatb.2022.122088



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