Mechanically induced Cu active sites for selective C-C coupling in CO2 electroreduction

Developing a convenient method to endow bulk Cu-based electrode with high activity of electrocatalytic CO2 reduction reaction (CO2RR) to multicarbon (C2+) products is desirable but challenging. Herein, for the first time, we report that mechanical polishing induces highly reactive Cu sites for selective C-C coupling in CO2RR. We find that mechanical polishing could endow Cu foil with abundant nanocavity surface structure, which efficiently confines the carbonaceous intermediates to enhance the probability of C-C coupling reaction. By confining the carbonaceous intermediates with Cu nanocavity, the as-prepared electrode delivers a Faradaic efficiency toward C2+ products of 65.7% at −1.3 V vs. RHE, which is enhanced up to 1.7 folds compared with that of commercial Cu foil. This work provides a new method to enable Cu foil with high activity of CO2RR to C2+ products.