Insights into the mechanism in electrochemical CO(2) reduction over single-atom copper alloy catalysts: A DFT study

Copper single-atom alloy catalysts (M@Cu SAAs) have shown great promise for electrochemical CO(2) reduction reaction (CO(2)RR). However, a clear understanding of the CO(2)RR process on M@Cu SAAs is still lacking. This study uses density functional theoretical (DFT) calculations to obtain a comprehensive mechanism and the origin of activity of M@Cu SAAs. The importance of the adsorption mode of M@Cu is revealed: key intermediates either adsorbed in the adjacent hollow site around Cu atoms (AD mode) or adsorbed directly on the top site of M (SE mode). AD mode generally exhibits finely tuned binding strengths of key intermediates, which significantly enhances the activity of the catalysts. Increasing the coverage of ∗CO on the M@Cu with SE mode leads to relocation of the active site, resulting in improved activity of C(2) products. The insights gained in this work have significant implications for rational design strategy toward efficient CO(2)RR electrocatalysts.