d-band center engineering of single Cu atom and atomic Ni clusters for enhancing electrochemical CO 2 reduction to CO

The rational design of catalysts with atomic dispersion and a deep understanding of the catalytic mechanism is crucial for achieving high performance in CO 2 reduction reaction (CO 2 RR). Herein, we present an atomically dispersed electrocatalyst with single Cu atom and atomic Ni clusters supported on N-doped mesoporous hollow carbon sphere (Cu SA Ni AC /NMHCS) for highly efficient CO 2 RR. Cu SA Ni AC /NMHCS demonstrates a remarkable CO Faradaic efficiency (FE CO ) exceeding 90% across a potential range of -0.6 to -1.2 V vs. reversible hydrogen electrode (RHE) and achieves its peak FE CO of 98% at -0.9 V vs. RHE. Theoretical studies reveal that the electron redistribution and modulated electronic structure - notably the positive shift in d-band center of Ni 3 d orbital - resulting from the combination of single Cu atom and atomic Ni clusters markedly enhance the CO 2 adsorption, facilitate the formation of *COOH intermediate, and thus promote the CO production activity. This study offers fresh perspectives on fabricating atomically dispersed catalysts with superior CO 2 RR performance.