Progress in Research on High-Efficiency Non-Noble Metal Acetylene Hydrogenation Catalysts
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[ Instrument R&D of Instrument Network ] Selective hydrogenation of acetylene is an essential step in the petrochemical production process. In industry, a small amount of acetylene (0.5%-2%) remaining in the ethylene feed gas is removed by catalytic hydrogenation to avoid poisoning and deactivation of the catalyst for the next polymerization reaction. Studies have shown that noble metal palladium can exhibit higher activity and selectivity in this reaction than other metals, and the introduction of second metal components, surface modification and other control measures can further improve its ethylene selectivity and develop efficient palladium Acetylene selective hydrogenation catalyst. However, the expensive price of precious metal palladium has greatly increased production costs, so the development of cheap non-precious metal catalysts has been a hot spot in the catalytic industry and scientific research.
In recent years, important progress has been made in the design and development of non-noble metal acetylene selective hydrogenation catalysts, but there are still many problems, such as difficulties in preparation, low activity, and insufficient selectivity. Therefore, the design and development of new and efficient non-noble metal acetylene selective hydrogenation catalysts are the focus of industrial production and scientific research. The design of the catalyst is highly dependent on the establishment of structure-activity relationship, and the accurate analysis of the structure is its primary problem. In the past, the characterization of the catalyst structure was usually based on ex-situ methods, but some sensitive catalysts will interact with oxygen in the air to cause structural changes. Therefore, the structure obtained by ex-situ methods usually exists with the active structure in the real catalytic environment. Differences make it difficult to understand catalytic mechanisms and establish structure-activity relationships. In recent years, the development of in-situ technology has made it possible to characterize the active structure and evolution of catalysts in the chemical environment. Related research results have greatly promoted structural analysis and recognition of catalytic mechanisms.
The research team of Zhang Bingsen from the Joint Research Department of Shenyang National Research Center for Materials Science, Institute of Metal Research, Chinese Academy of Sciences has been devoted to the structural analysis, design and development of acetylene selective hydrogenation catalysts. Through various in-situ methods, the active structure formation of the acetylene selective hydrogenation catalyst and its evolution under reaction conditions were analyzed, and related to the reaction performance, in order to accurately establish the "synthesis conditions-active structure of the acetylene selective hydrogenation catalyst -Response performance" to establish a foundation, and then provide guidance for the design of high-efficiency hydrogenation catalysts. Recently, based on the research work of the research team on the acetylene selective hydrogenation catalyst (Chem. Commun. 2020, 56, 6372; Angew. Chem. Int. Ed. 2019, 58, 4232; ChemCatChem 2017, 9, 3435), metal Researcher Zhang Bingsen, Professor Wei Wei of Beijing University of Chemical Technology, Professor Zhang Wei of Jilin University, and Dr. Huang Xing, Marc-Georg Willinger of the Swiss Federal Institute of Technology in Zurich, Switzerland, and others collaborated to introduce precise nickel electronic structure and octahedral gap volume by introducing zinc atoms The regulation captured the complete process of acetylene's spontaneous adsorption, dissociation on the surface of nickel-based nanoparticles, and the formation of interstitial carbide Ni3ZnC0.7. The catalyst structure and its evolution were characterized by in-situ X-ray diffraction, in-situ synchrotron radiation, and transmission electron microscopy. It was found that interstitial carbon atoms can effectively regulate the nickel atoms through coordination with six nickel atoms The distance and electronic structure improve its selectivity and stability in the selective hydrogenation of acetylene. This work provides new ideas for the design and preparation of highly efficient non-noble metal hydrogenation catalysts.
Relevant research results were published in Nature Communications recently, and the first author of the paper was Niu Yiming, PhD of the Institute of Metallurgy.
This work was supported by the National Natural Science Foundation of China, the “Xingliao Talents Program†project of Liaoning Province, and the Youth Innovation Promotion Association of the Chinese Academy of Sciences.