Customizable CO2 Electroreduction to C1 or C2+ Products through Cuy/CeO2 Interface Engineering

Cu-catalyzed CO2 electroreduction can produce various hydrocarbons and oxygenates. However, it suffers from low activity and poor selectivity. Herein, Cu-decorated CeO2 composites (Cuy/CeO2) with distinct interfacial characteristics were fabricated through a highly controllable synthesis, based on chemical prelithiation of CeO2 and then galvanic displacement with Cu. The Cu decoration induced a strong-binding site for CO2 adsorption at the Cu and CeO2 interface, facilitating the CO2 activation and conversion to the *CO intermediate on the nearby Cu surface. Selective CO2 conversion to C1 or C2+ products was customized by adjusting the Cu decoration amount. With the increase in the Cu loading, the C1 and C2+ products exhibited a declining and volcano-shaped trend, showing a maximum faradaic efficiency of 70 and 63%, respectively. In situ infrared and Raman spectroscopy revealed that the reduction pathway depended on the relative ratio of the low-frequency band *COLFB to the high-frequency band *COHFB. Our findings may contribute to the rational design of heterostructured catalysts toward CO2 electroreduction.