▎ 摘　　要

The catalytic CO oxidative coupling to dimethyl oxalate (DMO) was studied by means of density functional theory (DFT) calculations, and effects of different sizes of Pd-n cluster and different defective graphenes on this reaction were also discussed. A series of different sizes of Pd-n (n = 1, 4 and 6) anchored on single-vacancy graphene (SVG) was firstly constructed, and the results show that the Pd-SVG catalyst shows remarkable catalytic activity for CO oxidative coupling to DMO. In addition, the single Pd atom supported on different defective graphenes were studied to reveal the effect of the vacancy type of graphene on reaction activity and selectivity. It showes that the favorable pathway is CO-COOCH3 coupling path on the Pd supported on the graphene with double vacancy (DVG), which has excellent activity and selectivity. Therefore, Pd-DVG can be considered as effective catalyst to enhance the catalytic performance and greatly reduce cost of noble Pd-based catalysts.