Exploring the catalytic mechanisms of non-noble VIIIB metal dimer embedded in graphene toward CO oxidation by density functional theory analysis

Abstract Development of highly efficient, cost effective heteronuclear catalysts has been a huge interest in recent years due to its prime importance in environmental perpetuation. Among the developed catalysts, heteroatom-doped graphene catalysts for CO oxidation have attracted a global attention, due to its unique electronic properties suitable for CO oxidation. In this work, the oxidation mechanism of CO on various VIIIB dimeric metal-doped graphene with four atom vacancies systems (M1M2@C6) were investigated systematically by density functional theory (DFT) calculations. After a detailed analytic investigation through competition of adsorption performance and stability, FeFe@C6, FeCo@C6 and FeNi@C6 were found to be highly efficient and suitable as CO oxidation catalysts. Further, the heteronuclear dimeric catalysts (FeCo@C6 and FeNi@C6) were found to possess better catalytic activity over homonuclear dimeric catalyst (FeFe@C6) with much lower energy barrier for CO oxidation (0.79 eV, 0.49 eV, 0.42 eV for FeFe@C6, FeCo@C6, FeNi@C6). This investigation opens a new direction in designing the efficient and cost-effective graphene-based catalysts and also provides important hints for the understanding of catalytic reaction mechanisms for CO oxidation catalysis, which provides guidance and ideas for subsequent experimental synthesis of low-cost and efficient catalysts.