Vanadium‐Doped Ni3S2: Morphological Evolution for Enhanced Industrial‐Scale Water and Urea Electrolysis

Abstract The development of an earth abundant, cost‐effective, facile and multifunctional 3D‐porous catalytic network for green hydrogen production is a tremendous challenge. Herein, we report the V‐Ni 3 S 2 self‐supported catalytic network with optimized morphology grown directly on nickel foam (NF) by the one‐step hydrothermal technique for water and urea electrolysis at industrial scale hydrogen generation. The morphology of Ni 3 S 2 was modulated by doping of different concentrations of vanadium from granules to cross‐linked wires to hierarchal nanosheets arrays, which is beneficial in electrochemical charge and mass transport, and generates more exposed active sites. The V‐Ni 3 S 2 catalyst requires the overpotential of 147 mV for hydrogen evolution reaction (HER). The OER and UOR half‐cell reaction on V‐Ni 3 S 2 catalyst requires potential 1.57 V and 1.39 V (vs RHE), respectively to generate current 100 mA/cm 2 . The water electrolysis cell developed by V‐Ni 3 S 2 as both anode and cathode generates 100 mA/cm 2 at cell voltage of 1.88 V in laboratory condition (1 M KOH, 25 °C) and 1.61 V at industrial condition (5 M KOH, 80 °C) and also shows considerable stability for 82 hr at current 300 mA/cm 2 . The urea electrolysis cell with 1 M KOH and 0.33 M urea generates 100 mA/cm 2 at a cell voltage of 1.73 V, which is 150 mV less than that required for water electrolysis and demonstrate stability for 85 hr at a current of 100 mA/cm 2 . The results provide an innovative plan for the considerate synthesis and design of bifunctional catalysts for energy storage and water splitting.