Illustration of the Intrinsic Mechanism of Reconstructed Cu Clusters for Enhanced CO 2 Electroreduction to Ethanol Production with Industrial Current Density.

Copper-based catalysts have been attracting increasing attention for CO 2 electroreduction into value-added multicarbon chemicals. However, most Cu-based catalysts are designed for ethylene production, while ethanol production with high Faradaic efficiency at high current density still remains a great challenge. Herein, Cu clusters supported on single-atom Cu dispersed nitrogen-doped carbon (Cu x /Cu-N/C) show ethanol Faradaic efficiency of ∼40% and partial current density of ∼350 mA cm -2 . Quasi in situ X-ray photoelectron spectroscopy and operando X-ray absorption spectroscopy results suggest the generation of surface asymmetrical sites of Cu + and Cu 0 as well as Cu clusters by electrochemical reduction and reconstruction during the CO 2 electroreduction process. Density functional theory calculations indicate that the interaction between Cu clusters and the Cu-N/C support enhances *CO adsorption, facilitates the C-C coupling step, and favors the hydrogenation rather than dehydroxylation of the critical intermediate *CHCOH toward ethanol in the bifurcation.