Ni─V Dual Sites Boost Nucleophilic Electrooxidation Coupling With Cathodic Hydrogen Production

ABSTRACT The integration of electrocatalytic 5‐hydroxymethylfurfural (HMF) oxidation with the hydrogen evolution reaction (HER) is a win‐win strategy that enables the concurrent production of high‐value chemicals and low‐energy hydrogen. However, HMF oxidation suffers from competing adsorption between organics and OH ⁻ along with continuous redox cycling of active sites, leading to unsatisfactory activity, selectivity, and stability. To address these challenges, we designed a VO ₂ /Ni ₃ S ₂ composite catalyst with rich cationic vacancies and low vanadium content. This catalyst creates Ni─V dual active sites that trigger an alternative reaction pathway. VO ₂ /Ni ₃ S ₂ achieves high HMF conversion (97.1%), Faradaic efficiency (96.0%), and selectivity (98.93%) toward FDCA, along with robust stability. In an integrated HMFOR||HER system using VO ₂ /Ni ₃ S ₂ for both electrodes, a current density of 100 mA cm ⁻² was attained at a low cell voltage of 1.76 V. Mechanistic studies reveal that VO ₂ ‐induced vacancies promote the formation of high‐valence Ni species, while adjacent V sites enhance OH adsorption. This configuration enables balanced co‐adsorption of HMF and OH ⁻ . Unlike conventional single‐site Ni catalysis, the Ni─V dual sites optimize the dehydrogenation pathway while preserving the high oxidation state of Ni. This study sheds new light on the catalyst design for energy‐efficient biomass valorization and hydrogen production.