Kinetic analysis of hydrogen evolution at Ni–Mo alloy electrodes

The hydrogen evolution reaction (HER) on Ni, Mo and MoNi intermetallic compound was investigated with ac impedance and dc polarization measurements in 1.0 mol dm−3 NaOH solution at 25°C. The rate constants of the forward and backward reactions of Volmer, Heyrovsky and Tafel steps were estimated by a nonlinear fitting method. MoNi alloy electrode provides a much lower overpotential for the HER than Ni and Mo electrodes, sometimes which exhibit similar catalytic activity. The main pathway for the HER at above mentioned electrode materials is Volmer–Heyrovsky with Heyrovsky as the rate determining step.