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

We report the V‐Ni3S2 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 Ni3S2 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‐Ni3S2 catalyst requires the overpotential of 147 mV for hydrogen evolution reaction (HER). The OER and UOR half‐cell reaction on V‐Ni3S2 catalyst requires potential 1.57 V and 1.39 V (vs RHE), respectively to generate current 100 mA/cm2. The water electrolysis cell developed by V‐Ni3S2 as both anode and cathode generates 100 mA/cm2 at cell voltage of 1.88 V in laboratory condition (1M KOH, 25°C) and 1.61 V at industrial condition (5M KOH, 80°C) and also shows considerable stability for 82hr at current 300 mA/cm2. The urea electrolysis cell with 1M KOH and 0.33 M urea generates 100 mA/cm2 at a cell voltage of 1.73 V, which is 150 mV less than that required for water electrolysis and demonstrate stability for 85hr at a current of 100 mA/cm2.