Regulating Asymmetric C–C Coupling with Interfacial Alkalinity for Efficient CO ₂ to C ₂₊ Electroconversion

Abstract The electrocatalytic reduction of CO ₂ in neutral electrolytes is a promising avenue to minimize energy losses linked to carbonate formation. However, selectivity for multi‐carbon (C ₂₊ ) products is hampered by kinetic barriers in C–C coupling. Here, the regulation of asymmetric C–C coupling is achieved with interfacial alkalinity, facilitating efficient CO ₂ to C ₂₊ electroconversion. This is realized by co‐engineering copper electrodes with ZrO ₂ sites and CeO _x sites to enable a favorable microenvironment that greatly boosts intrinsic catalytic activity. In situ spectroscopic results and theoretical analyses demonstrates that CeO _x facilitates the dissociation of H ₂ O into *H and *OH, effectively regulating *H coverage at the catalytic interface and promoting the protonation of *CO to *COH. Meanwhile, ZrO ₂ sites significantly enhance the adsorption of in situ‐produced *OH, optimize the local pH on the Cu surface, and enable the formation of C ₂₊ products via a low‐energy *OC–COH coupling pathway. A notable CO ₂ to C ₂₊ electroconversion in 1.0 M KCl electrolyte, with Faraday efficiency of 67.2 ± 2.1% and a partial current density of 413.0 ± 9.9 mA cm ⁻² is achieved. This synergistic enhancement of hydroxyl adsorption and stabilization at the catalytic interface, driven by the activation of H ₂ O, is crucial for boosting the overall catalytic performance of the system.