Properties of nickel-based galvanic coatings as hydrogen evolution electrodes

The Ni–Mo–B coatings with a molybdenum content of 7–27 wt% and boron content of 0.75–1.36 wt% were obtained by electrochemical synthesis. Their surface morphology and elemental composition were analyzed using the methods of scanning electron microscopy, energy dispersive X-ray microanalysis and titrimetric method. The catalytic activity of the coatings in a 1 M KOH solution was evaluated by linear voltammetry, revealing that the molybdenum content has an influence on this activity. The hydrogen evolution reaction overpotential on the most effective catalyst was 0.194 V (j = 100 mA/cm²), with an exchange current density of 0.16 A/cm². The hydrogen evolution reaction on the coatings follows a combined Volmer–Heyrovsky mechanism. These results demonstrate the effectiveness of these coatings as electrocatalysts for the production of “green” hydrogen through alkaline electrolysis.