Differential Chloride Affinity Over Amorphous‐Crystalline Interfaces Drives Asymmetric C─C Coupling for Neutral CO 2 Electroreduction to Ethanol

ABSTRACT Electrocatalytic CO 2 reduction to ethanol in neutral electrolytes represents a promising pathway for carbon neutrality, yet the selectivity remains unsatisfactory due to inefficient C─C coupling and competitive hydrocarbon production. Herein, a copper oxide catalyst with enriched amorphous‐crystalline interfaces (IR‐CuO x ) exhibits differential Cl − affinity, effectively steering the CO 2 reduction pathway toward ethanol. The obtained IR‐CuO x catalyst achieves a remarkable ethanol Faradaic efficiency (FE) of 56.77% at −1.1 V vs. reversible hydrogen electrode (RHE) in 0.1 m KCl electrolyte. Impressively, with IR‐CuO x as the cathode, the integrated membrane electrode assembly (MEA) electrolyzer could stably operate for over 70 h under an industrial‐level current density of 200 mA·cm −2 , with ethanol FE remaining above 45%. Experimental characterizations and theoretical calculations demonstrate that the differential Cl − affinity over amorphous‐crystalline interfaces synergistically combines the * CO hydrogenation capability at weak Cl − affinity sites with the enhanced C─C coupling capability at strong Cl − affinity sites, favoring asymmetric * CO‐ * CHO coupling to generate the key * CHCOH intermediate. Additionally, the differential Cl − affinity further strengthens the C─O bond and weakens the Cu─C interaction, facilitating the hydrogenation of * CHCOH toward ethanol. This work offers fundamental understandings of surface anion adsorption behaviors for designing efficient electrocatalysts toward neutral CO 2 −to‐ethanol conversion.