The role of supported dual-atom on graphitic carbon nitride for selective and efficient CO 2 electrochemical reduction

Abstract The electrochemical reduction of CO 2 into value-added fuels and chemicals using single atom (SACs) or dual-atom catalysts (DACs) has been extensively studied, but the reaction mechanism and design rules are still unclear. Here, we studied the role of dual-metal atoms on graphite carbon nitride (M 1 M 2 @g-CN, M 1 M 2 = CuCu, FeFe, RuRu, RuCu, RuFe, CuFe) for selective and efficient CO 2 electrochemical reduction based on density functional theory. Our results show that CO 2 RR on RuRu@g-CN catalyst prefers the *COOH pathway, while for CuCu@g-CN, FeFe@g-CN, RuCu@g-CN, RuFe@g-CN, CuFe@g-CN catalysts, the *OCHO pathway is more suitable. Among all the DACs combinations, we found that RuCu@g-CN and RuFe@g-CN are the most promising electrocatalysts for CO 2 RR with a lower limiting potential, which is attributed to the synergistic effect of different O- and C-affinity of the heterocenters in DACs. The selectivity of RuCu@g-CN and RuFe@g-CN to the production of CH 4 is better than that of H 2 evolution. In addition, we also found that the adsorption free energy of intermediate on heteroatomic DACs can be predicted by those on homoatomic DACs, which can be used to further predict the limiting potential.