Preanodized Cu Surface for Selective CO2 Electroreduction to C1 or C2+ Products

The electrochemical CO2 reduction over Cu catalysts has shown great potential in producing a wide range of valuable chemicals, but it is still plagued by a poor controllability on product distribution. Herein, we demonstrate an effective regulation of CO2 reduction paths through a preanodization treatment of Cu foil electrodes in different electrolytes. The Cu electrode exhibits a superior C-1 and C2+ product selectivity after being preanodized in NaClO4 (Cu-NaClO4) and Na2HPO4 electrolyte (Cu-Na2HPO4), respectively. Combined with in situ electrochemical Raman, ATR-SEIRAS, and SEM characterizations, the preferential C-1 path is due to the deposition of many Cu nanocrystals with dominant Cu(111) facets on the Cu-NaClO4 electrode. In contrast, the preferential C2+ path over the Cu-Na2HPO4 is attributed to formation of a unique Cu nanodendritic morphology, which strengthens the *CO intermediate adsorption and induces an environment of low local H2O/CO2 stoichiometric ratio, thus facilitating C-C coupling for C2+ production. Our findings may shed light on the rational control of the CO2 reduction path through engineering of the Cu surface structure.

Automated summary

In this study, an effective regulation of CO2 reduction paths was demonstrated through preanodization treatment of Cu foil electrodes in different electrolytes. The rational control of the CO2 reduction path through engineering of the Cu surface structure was highlighted.