* OH Adsorption‐Mediated Electrochemical Oxidation of 5‐Hydroxymethylfurfural to Selective 2,5‐Furandicarboxylic Acid at pH 12

Abstract Strongly alkaline electrolytes are typically used for electrochemical 5‐hydroxymethylfurfural oxidation (HMFOR) to selective 2,5‐furandicarboxylic acid (FDCA) production, despite HMF degradation. Although HMF remains stable in weakly alkaline media, slow kinetics due to limited OH − concentration hinder active FDCA formation. Herein, unlike the CuO or NiOOH catalyst, significantly improved direct aldehyde oxidation is demonstrated via the utilization of adsorbed OH ( * OH) on the CuO/NiOOH interface surface, enabling complete conversion to FDCA even at mild pH. Operando measurements reveal that the CuO/NiOOH interface serves as a synergistic active site: Cu sites enhance * OH adsorption and utilization, while Ni sites promote HMF dehydrogenation through rapid Ni(OH) 2 /NiOOH redox cycling. The synergistic effect promotes highly selective FDCA production while preventing prematur…