Efficient Electrooxidation of 5‐Hydroxymethylfurfural Using Co‐Doped Ni3S2 Catalyst: Promising for H2 Production under Industrial‐Level Current Density

Abstract Replacing oxygen evolution reaction (OER) by electrooxidations of organic compounds has been considered as a promising approach to enhance the energy conversion efficiency of the electrolytic water splitting proces. Developing efficient electrocatalysts with low potentials and high current densities is crucial for the large‐scale productions of H 2 and other value‐added chemicals. Herein, non‐noble metal electrocatalysts Co‐doped Ni 3 S 2 self‐supported on a Ni foam (NF) substrate are prepared and used as catalysts for 5‐hydroxymethylfurfural (HMF) oxidation reaction (HMFOR) under alkaline aqueous conditions. For HMFOR, the Co 0.4 NiS@NF electode achieves an extremely low onset potential of 0.9 V versus reversible hydrogen electrode (RHE) and records a large current density of 497 mA cm –2 at 1.45 V versus RHE for HMFOR. During the HMFOR‐assisted H 2 production, the yield rates of 2,5‐furandicarboxylic acid (FDCA) and H 2 in a 10 mL electrolyte containing 10 × 10 −3 M HMF are 330.4 µmol cm –2 h –1 and 1000 µmol cm –2 h –1 , respectively. The Co 0.4 NiS@NF electrocatalyst displays a good cycling durability toward HMFOR and can be used for the electrooxidation of other biomass‐derived chemicals. The findings present a facile route based on heteroatom doping to fabricate high‐performance catalyses that can facilitate the industrial‐level H 2 production by coupling the conventional HER cathodic processes with HMFOR.