The catalysts are involved in more than 80% of industrial production processes, such as chemical production, energy transition, pharmaceuticals, and wastes disposal. To cater for the increasing production demands and maximum economic benefits, the development of high-efficiency, stable and low-cost novel catalysts has become a top priority. As a new field in the catalysis, single atom catalysts (SACs) provide the smallest active site and the highest metal atom utilization, which can bring higher economic benefits. Meanwhile, the atom-support microstructure can be rationally modified, which allows scientists to control the geometric structure and electronic structure of the active sites, thereby regulating the catalytic activity and selectivity. However, SACs often suffer from sintering in the actual thermal catalytic application process. Therefore, it is particularly important to rationally design SACs from the atomic structure to obtain thermally stable SACs.
Recently, a research team led by Prof. Yuen Wu from University of Science and Technology of China reviewed the rational construction and practical application of thermally stable SACs. To fabricate thermally stable SACs rationally, it is necessary to understand the interaction between single metal atoms and supports in depth, which is the basis for understanding the thermal stability of the SACs. The weak physical interaction (van der Waals forces or electrostatic interactions) usually fails to restrain migration and aggregation of metal atoms under the interference of external conditions (high temperature, reducing atmosphere…). In comparison, constructing chemical interaction between metal atoms and supports surface by strong coordination interactions or surface lattice reconstruction is more likely to access thermally stable SACs. Therefore, it is theoretically feasible to obtain thermally stable SACs by constructing strong chemical interaction between metal atoms and supports. On this basis, this review combined the research results in recent years and summarized a series of synthetic methods for thermally stable SACs, such as high temperature pyrolysis, high-temperature migration, heteroatom-doped thermal atomization, etc..
As for practical applications, this review combined novel characterization techniques and calculation methods to study the catalytic mechanism of thermally stable SACs during the thermocatalytic process. Thermally stable SACs were intensively studied in reactions like CO oxidation, CH4 oxidation, selective hydrogenation reaction and so on.
For the demand of fundamental research and industrial applications of thermocatalysis, enhancing the active site density of SACs and achieving the large-scale and facile preparation of thermally stable SACs are currently two major challenges. In this regard, rational design of the coordination structure of metal atoms is necessary, which contributes much to improvement and optimization of the catalytic properties of thermally stable SACs. With novel in situ characterization technologies, researchers can observe the dynamic changes during the process of synthesis and catalytic reactions more clearly and thus prepare improved catalysts accordingly. To realize the commercialization of thermally stable SACs, the large-scale and facile preparation of thermally stable SACs is another research direction. If these challenges are overwhelmed, it can be expected that the development of single atom catalysis will open a new page. This review was published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(21)63888-3).
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 six journals in Applied Chemistry with a current SCI impact factor of 8.271. The Editors-in-Chief are Profs. Can Li and Tao Zhang.
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