Activating Co 2+ /Co 3+ Redox Couple Mediated‐Electrooxidation of 5‐Hydroxymethyl Furfuryl Under Low Potentials

Abstract Cobalt‐based electrocatalysts are promising candidates for electrochemical 5‐hydroxymethylfurfural oxidation reaction (eHMFOR). However, the activity origin for eHMFOR on most cobalt‐based electrocatalysts is the Co 3+ /Co 4+ redox couple at the high‐potential window, instead of the Co 2+ /Co 3+ redox couple at the low‐potential window, thus leading to a high onset potential above 1.3 V. Herein, we developed F‐V O ‐CoMoO 4 catalyst containing abound oxygen vacancies and lattice fluorine (F) heteroatom, which activates the Co 2+ /Co 3+ redox couple for eHMFOR at the low‐potential window, e.g., 1.15 V. Oxygen vacancies prompt the electrochemical generation of Co 3+ ‐OH ads at low potentials, and meanwhile, lattice F heteroatoms enhance the electrophilicity of Co 3+ ‐OH ads . Benefiting by those unique structure, F‐V O ‐CoMoO 4 catalyst effectively electro‐synthesizes 2,5‐furandicarboxylic acid from 5‐hydroxymethylfurfural, with a high yield (95.3%) and Faradaic efficiency (96.1%). This work provides an intelligent strategy for achieving the low‐potential eHMFOR mediated by the Co 2+ /Co 3+ redox couple, unlocking significant potential for reducing the energy consumption in biomass conversion.