The electronic interaction of encapsulating graphene layers with FeCo alloy promotes efficient CO2 hydrogenation to light olefins

With the development of industrialization, the rapid increase of CO₂ emission from extensive uses of fossil energy brings severe impacts on environment and climate. Thermal catalytic CO₂ hydrogenation has attracted widespread attention due to its high conversion efficiency and higher value of the products. The Fe-based catalysts with high C-O activation and C-C coupling capabilities have become the research focus for CO₂ hydrogenation to produce value-added chemicals. Although significant progress has been made in improving the catalytic performance of Fe-based catalysts, a formidable challenge in highly efficient and stable conversion of CO₂ to target products still lingers. Therefore, this requires catalysts to maintain stable active phase and possess moderate CO₂ adsorption activation ability during the reaction process.

Catalysts are usually rich in bonding sites and electrons, which form chemical bonds and exchange electrons with reactant molecules to adsorb and activate them. Therefore, regulation of the electronic structure of the active phase of the catalysts can effectively improve the adsorption behavior of reactant molecules, thereby enhancing the catalytic conversion efficiency. Curved graphene or carbon nanotubes formed by many rolled-up graphene layers exhibit completely different electronic properties between the interior and exterior because of the shift of π-electron density from the concave inner surface to the convex outer surface, which is of great significance in regulating the electronic properties and phase evolution of the active phase

Recently, a research team led by Prof. Xinwen Guo from Dalian University of Technology reported a FeCo alloy catalyst encapsulated by graphene layer based on a simple method for regulating the electronic structure of the active phase, achieving efficient and stable conversion of CO₂ to light olefins. The FeCo alloy catalysts encapsulated in graphene layers were prepared by the simple sol-gel method based on the complexation of polyvinyl pyrrolidone (PVP) with metal ions. Metal ions were well dispersed due to the complexation effect and the alloy particles were uniformly separated by the graphene layers after subsequent pyrolysis treatment. The characterization results confirmed that the catalysts show a core-shell structure of graphene layers encapsulated FeCo alloy nanoparticles, and the electron transfer from Fe species to the inner surface of bent graphene. The electronic interaction, close intimacy of Fe and Co sites, high dispersion of the active phase ensure the excellent performance with 52.0% CO₂ conversion, 33.0% selectivity to light olefins, and stability for over 100 h of FeCoK@C catalyst. The light olefins space time yield can be further improved to unprecedented 52.9 mmol_CO2·g^-1·h^-1 demonstrating its potential for practical application. This work provides an effective strategy for the design, preparation, and application of high-performance catalysts for CO₂ hydrogenation. The results were published in Chinese Journal of Catalysis (https://doi.org/10.1016/S1872-2067(24)60188-9)

About the Journal

Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top one journals in Applied Chemistry with a current SCI impact factor of 15.7. The Editors-in-Chief are Profs. Can Li and Tao Zhang.

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