Harnessing Interfacial Cl ⁻ Ions for Concurrent Formate Production at Industrial Level via CO ₂ Reduction and Methanol Oxidation

Abstract The efficient electrocatalytic conversion of CO 2 to formate is often impeded by the high energy requirements of the oxygen evolution reaction (OER) and the limited activity and selectivity of CO 2 reduction reaction (CO 2 RR). Herein, a novel strategy to enhance formate production by substituting the OER with the methanol oxidation reaction (MOR) and optimizing the cathodic microenvironment with interfacial Cl − ions is presented. Through theoretical analysis, binder‐free Bi and NiOOH electrodes that achieve remarkable Faradaic efficiencies (FE formate ) exceeding 90% at current densities of 50–250 mA·cm −2 for CO 2 RR and MOR, respectively, are identified. These combined experimental and theoretical investigations demonstrate that interfacial Cl − enrichment on the Bi electrode modulates the local electronic structure, fostering a microenvironment conducive to CO 2 RR. The Bi–NiOOH full cell maintains a FE formate above 90% at industry‐level current densities (100–300 mA·cm −2 ), enabling concurrent formate electrosynthesis at both electrodes. This work highlights the critical role of local anion environments in electrocatalysis and provides a strategic framework for the synergistic engineering of electrochemical systems.