摘要
A single-atom catalyst （SAC） that was first proposed by us in 2011 has aroused significant recent interest. Among the various SACs, FeOx-based ones including Pt1/FeOx, Ir1/FeOx, Au1/FeOx, Ni1/FeOx, and Fe1/FeOx have been investigated either experimentally or theoretically for CO oxidation. However, a systematic study of FeO,-based SACs has not been conducted. For a comprehensive understanding of FeOx-supported single-metal-atom catalysts, extensive density functional theory calculations were carried out on the activities and catalytic mechanisms of SACs with the 3d, 4d, and 5d metals of group VIII to IB, i.e., M1/FeOx （M = Fe, Co, Ni, Cu; Ru, Rh, Pd, Ag; Os, Ir, Pt, Au） for CO oxidation. Remarkably, a new noble metal SAC, Pd1/FeOx, with high activity in CO oxidation was found and is predicted to be even better than the previously reported Pt1/FeOx and Ni1/FeOx. In comparison, other M1/FeOx SACs （M = Fe, Co, Cu; Ru, Rh, Ag; Os, Ir, Au） showed only low activities in CO oxidation. Moreover, the adsorption strength of CO on the single-atom active sites was found to be the key in determining the catalytic activity of these SACs for CO oxidation, because it governs the recoverability of oxygen vacancies on their surfaces in the formation of a second CO2 during CO oxidation. Our systematic studies of FeOx-supported SACs will help in understanding the fundamental mechanisms of the interactions between singly dispersed surface metal atoms and FeOx substrate and in designing highly active FeOx-supported SACs.
A single-atom catalyst （SAC） that was first proposed by us in 2011 has aroused significant recent interest. Among the various SACs, FeOx-based ones including Pt1/FeOx, Ir1/FeOx, Au1/FeOx, Ni1/FeOx, and Fe1/FeOx have been investigated either experimentally or theoretically for CO oxidation. However, a systematic study of FeO,-based SACs has not been conducted. For a comprehensive understanding of FeOx-supported single-metal-atom catalysts, extensive density functional theory calculations were carried out on the activities and catalytic mechanisms of SACs with the 3d, 4d, and 5d metals of group VIII to IB, i.e., M1/FeOx （M = Fe, Co, Ni, Cu; Ru, Rh, Pd, Ag; Os, Ir, Pt, Au） for CO oxidation. Remarkably, a new noble metal SAC, Pd1/FeOx, with high activity in CO oxidation was found and is predicted to be even better than the previously reported Pt1/FeOx and Ni1/FeOx. In comparison, other M1/FeOx SACs （M = Fe, Co, Cu; Ru, Rh, Ag; Os, Ir, Au） showed only low activities in CO oxidation. Moreover, the adsorption strength of CO on the single-atom active sites was found to be the key in determining the catalytic activity of these SACs for CO oxidation, because it governs the recoverability of oxygen vacancies on their surfaces in the formation of a second CO2 during CO oxidation. Our systematic studies of FeOx-supported SACs will help in understanding the fundamental mechanisms of the interactions between singly dispersed surface metal atoms and FeOx substrate and in designing highly active FeOx-supported SACs.
基金
We acknowledge simulating discussion with Professor Qingfeng Ge. This work was supported by the National Natural Science Foundation of China （Nos. 21590792, 91645203, and 21521091 to J. L.
21503046 to J. X. L. and 21203182 to X. F. Y.）, and National Basic Research Program of China （No. 2013CB834603 to J. L.）, Natural Science Foundation of Guizhou Province of China （No. QKJ[201512122）, Natural Science foundation of Department of Education of Guizhou Province （Nos. QJTD[2015155 and ZDXK[2014]18） and the GZEU start up package. The calculations were done using supercomputers at Tsinghua National Laboratory for Information Science and Technology, the State Key Laboratory of Physical Chemistry of Solid Surfaces （Xiamen University）, and Guizhou Provincial High- Performance Computing Center of Condensed Materials and Molecular Simulation. This project is partially supported by the Open Fund of Shaanxi Key Laboratory of Catalysis to J. X. L. （No. SXKLC-2017-01）.
