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 de polarization measurements in 1.0 mol dm(-3) NaOH solution at 25 degrees 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. (C) 2000 Elsevier Science Ltd. All rights reserved.