Enhanced Electrocatalytic Conversion of CO2 to C2+ Products via Intermediate Stabilized Cu+/Cu0 Interface Catalysts

Electrocatalytic reduction reaction of CO2 (CO2RR) into value-added multicarbon (C2+) products represents a sustainable strategy for mitigating greenhouse gas emissions and enhancing the production of high-value chemicals. Cu-based catalysts are optimal for the CO2RR, facilitating the generation of C2+ products such as ethanol, which have significant industrial applications. However, converting CO2 to C2+ products remains a great challenge, necessitating the simultaneous achievement of high current density, Faradaic efficiency (FE), and operational stability for industrial-scale implementation. Herein, we prepared Cu/Cu2O catalysts with diverse morphologies and the ratio of the Cu+/Cu interface, which was rectified by regulating the interactions between the active interface and the intermediate (*CO). The electrochemical analysis demonstrated that reconstructed Cu/Cu2O nanodendrites with dominant grain boundaries exhibited remarkable performance in generating C2+ products, achieving a Faradaic efficiency (FE) of 71.8%, including 49.7% FE of ethanol and a substantial partial current density of 390.0 mA cm–2 within the flow cell. In situ spectroscopy characterization and theoretical calculations revealed that the increased ethanol selectivity originated from the rectification of the Cu/Cu2O interface by the *CO intermediate, which accelerated H2O dissociation, reduced the free energy for *CO hydrogenation to *COH, and facilitated asymmetric *CO-*COH coupling to preferentially reduce CO2 to ethanol. This study provides profound insights into the C–C coupling pathways and sheds light on the rational design of ethanol-oriented electrocatalysts, contributing to sustainable chemical synthesis and energy utilization.