Abstract：The catalytic performance of the supported metal catalysts mainly depends on the design of metal active center. In this study, C2 oxygenates synthesis from syngas over the nitrogen-doped grapheme (NC)-supported metal diatomic catalysts had been investigated using the density functional theory calculations, the homonuclear diatomic catalysts (CuCu@NC, RhRh@NC and CoCo@NC) and heteronuclear diatomic catalysts (CuRh@NC, RhCo@NC and CuCo@NC) were considered. The results showed that six kinds of diatomic catalysts have good stability, meanwhile, CHx formation activity followed the order of CuRh@NC>RhCo@NC>CuCo@NC>CuCu@NC>RhRh@NC>CoCo@NC, and the order of CHx selectivity was RhCo@NC>CoCo@NC>RhRh@NC>CuCo@NC>CuRh@NC>CuCu@NC. Subsequently, once the most favored CHx intermediate was formed, CHO insertion into CHx could easily generate C2 oxygenates with high activity and selectivity. Considering the catalytic activity and selectivity, RhCo@NC was screened out to be the best catalyst for C2 oxygenates synthesis from syngas, in which the metal Rh inhibits methanol formation, and Co promoted the C—O bond cleavage to generate CHx. The synergetic effect of Rh and Co co-catalyzes the formation of CH2 and promoted the C—C chain formation of C2 oxygenates. The electronic property analysis showed that the moderate charge transfer of the active component was beneficial to the improvement of catalytic performance. The ab initio molecular dynamics (AIMD) simulation of RhCo@NC catalyst at 525 K showed that the catalyst had better thermal stability. This study clearly elucidated the essential attribute about the influence of adjacent bimetallic active centers on catalytic performance and provided reasonable guidance for the design of highly efficient catalysts.
CHANG Zehai,WANG Baojun,LING Lixia et al. The Regulation of Catalytic Performance for C2 Oxygenates Synthesis from Syngas over the Nitrogen-Doped Graphene-Supported Metaldiatomic Catalysts[J]. Chemical Reaction Engineering and Technology, 2021, 37(6): 534-547.
