Electrocatalytic characterization of Ni–Fe–TiO₂ overlayers for hydrogen evolution reaction in alkaline solution

The Ni–Fe–TiO₂ overlayers on mild steel strips were prepared by electrochemical deposition. The layers were characterized morphologically by confocal laser scanning microscopy and scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) analysis. The layers exhibit a quasi-three-dimensional (3D) morphology in which the crystalline, TiO₂, is embedded. Electrocatalytic activity of the Ni–Fe–TiO₂ layers for the hydrogen evolution reaction (HER) was assessed by using pseudo-steady-state polarization curves and electrochemical impedance spectroscopy (EIS) in alkaline solution. The results were compared with the properties of Ni–Fe electrodes and used for determining the mechanism and kinetics of HER. In comparison with Ni–Fe electrodes, the synthesized Ni–Fe–TiO₂ electrodes present higher catalytic activity for HER due to the increase in the real surface area and high intrinsic electrocatalytic activity of titanium dioxide. The present study provides valuable insight for exploring practical applications of Ni-based alloys as hydrogen evolution electrodes.