Synergistic Cu+/Cu0 on Cu2O-Cu interfaces for efficient and selective C2+ production in electrocatalytic CO2 conversion

The electrocatalytic CO2 reduction technology is expected to simultaneously alleviate increasing CO2 emissions and the depletion of fossil resources. However, it is still a big challenge to improve the selectivity toward valuable multi-carbon products in electrocatalytic CO2 reduction reaction. In this study, the synergistic role of Cu+ and Cu0 species in Cu2O-Cu interfaces is unravelled through density functional theory (DFT) calculations, in which the electrode surface exhibits low free energy of *COCO intermediate formation and H2O dissociation, which are beneficial to the high selectivity towards multi-carbon products, especially C2H4. Guided by these DFT results, an oxide-derived copper electrode activation strategy that builds the synergistic Cu+ and Cu0 on Cu2O-Cu interfaces is designed to boost the selectivity toward multi-carbon products. Interestingly, Cu2O cubes chosen as the pristine catalyst are activated via a square-wave (SW) potential treatment to form SW-Cu2O cubes that bear Cu+ and Cu0 species. The as-prepared SW-Cu2O cubes exhibit superior Faradaic efficiencies for C2H4 (60%) and C2+ products (75%) in an H-type cell, which are about 1.5 times that of the Cu2O cubes. This study demonstrates the synergistic Cu0 and Cu+ on Cu2O-Cu interfaces for improving the selectivity of a specific valuable multi-carbon product in electrocatalytic CO2 conversion.