Autogenetic Carbon Oxyanions Enable Interfacial OH− Deconfinement for Reinforced Biomass Electrooxidation over Wide Potential Window

Abstract The preferential adsorption toward OH − on the anode most likely blocks the accessibility of organic molecules and triggers competitive oxygen evolution reaction (OER), typically precipitating a narrow potential window. Here, an OH − deconfinement strategy enabled by CO 3 2− self‐transformed from C 2 O 4 2− on metallic nickel oxalate (NiC 2 O 4 ) for efficient synthesis of bioplastic monomer 2,5‐furanedicarboxylic acid (FDCA) with faradaic efficiency of >95% via electrocatalytic 5‐hydroxymethylfurfural (HMF) oxidation reaction (e‐HMFOR) at a wider potential window of 1.38–1.56 V RHE , outperforming state‐of‐the‐art Ni‐based electrocatalysts is presented. In situ, tests corroborate that the construction of NiOOH with surface‐adsorbed CO 3 2− (NiOOH‐CO 3 2− ) from NiC 2 O 4 can be facilitated by self‐liberating CO 3 2− . The CO 3 2− ions serving as an electric field engine can effectively weaken OH − coverage through electrostatic repulsion and enhance HMF adsorption at the NiOOH‐CO 3 2− surface, thereby heightening e‐HMFOR while inhibiting OER. Computational results further indicate that the CO 3 2− on NiOOH hoists the energy barrier of oxygen intermediate conversion (O* → OOH*) to suppress OER but promotes the e‐HMFOR kinetics. The precise modulation of OH − adsorption behavior on the electrocatalyst offers a powerful kit for boosting the oxidative upgrading process while circumventing the competing reaction OER.