Optimization of Ni-Mo-Coated Stainless Steel as a High-Performance Cathode in Alkaline Water Electrolysis

Considering the widespread use of alkaline water electrolysis (AWE) in the chemical industry and the growing need to design and manufacture low-cost and efficient electrodes, the optimization of a Ni-Mo-coated stainless steel substrate is investigated in the present work to use this substrate as a cathode of an alkaline water electrolyzer. The crystallographic structure, surface morphology, and composition of the optimized coating are characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and surface elemental mapping. The electrocatalytic activity for the hydrogen evolution reaction (HER) is evaluated by making electrochemical measurements. In addition, the optimization of the electrodeposition bath is investigated to promote the HER activity. The results show that nickel-molybdenum (1:2) alloy exhibits a higher HER activity, and a current density of 180 mA cm −2 is achieved at −1.7 V vs. Ag/AgCl using this coating. Also, the polarization curves of the electrolysis cell demonstrate that using the optimized cathode, the cell operates at 1.9 V at a current density of 1.5 A.cm −2 and the operating temperature of 60 °C, which is suitable for use in large-scale industrial AWE units. Graphical Abstract