Protective Shield for Interfacial Cu ⁺ /Cu ⁰ Sites Enhances Multicarbon Production Toward Electrochemical Reduction of Carbon Dioxide

ABSTRACT The interface of Cu + /Cu 0 is a promising active site for multi‐carbon (C 2+ ) products towards the electrochemical reduction of carbon dioxide (CO 2 RR), whereas the cathodic environment commonly destroys this site by Cu + reduction. Herein, we introduced the acid radical of trimesic acid (BTC) by electrochemical reconstruction as a “protective shield” for the stabilization of the Cu + /Cu 0 interface. The BTC‐stabilized Cu + /Cu 0 interface displayed a Faradaic efficiency (FE) of 86.4 ± 2.4% for C 2+ products at 600 mA cm −2 towards CO 2 RR in neutral electrolyte, with the retention of Cu + /Cu 0 interface during the reaction. Such stabilization effect by BTC shield was attributed to the preferential trapping of the *H intermediates and decreased *H‐induced transfer and corrosion for Cu + . The BTC‐stabilized Cu + /Cu 0 interface displayed a distinct asymmetry coupling path between *CO and *COH, which lowered the energy barrier of C 2+ production. This work represents a new strategy for the stabilization of interfacial Cu + /Cu 0 sites towards CO 2 RR.