Kinetics of cathodic evolution of hydrogen on Ni-P systems electrodeposited alloys

Abstract

Analysis of experimental data on kinetics of hydrogen evolution reaction from sulfuric acid solutions on electrodeposited Ni,P alloys of various compositions is conducted. It is shown that changeover of mechanism of the process is observed upon increase of cathodic potential: at low overvoltages it occurs mainly via the Volmer-Heyrovsky pathway with control of the charge transfer stage, and the Volmer-Tafel mechanism, the slow stage of which is mechanical recombination, is realized at high potentials. The influence of the alloy composition on the parameters of the process is manifested in the change of charge transfer coefficients of both electrochemical stages and degree of surface filling by adsorbed hydrogen.