▎ 摘　　要

Copper dispersed on two-dimensional materials exhibits excellent catalytic performance for the electrochemical reduction reaction of CO2 (CO2RR). Here, Cu clusters were anchored on defective diamond graphene (Cu-n/ND@GR, n = 3, 4) to form a new class of two-dimensional nano-catalysts. Based on density functional theory, the catalytic performance and selective mechanisms of these configurations were studied systematically. By anchoring the appropriate number and configuration of Cu clusters on the defective graphene, specific reduction products (e.g., CO, CH4, and CH3OH) could be obtained. In particular, the inverted triangle configuration of Cu-3/ND@GR electroreduces CO2 to methane with an overpotential of only -0.53 eV. In addition, bonding analysis confirmed the stability of the Cu-n/ND@GR. The product selectivity was analyzed by calculating the deformation charge density, further revealing the CO2RR mechanism. Furthermore, side reactions (e.g., hydrogen evolution reaction and competitive production of formic acid) do not hinder the CO2RR catalytic activity. This research expands the family of catalysts for the CO2RR and the application scenarios of transition metals loaded on graphene, which provides new insights into the design and preparation of composite nano-catalysts.