An electrochemical study of the hydrogen evolution reaction at YNi2Ge2 and LaNi2Ge2 electrodes in alkaline solution

Abstract

The kinetics of the electrochemical hydrogen evolution on YNi2Ge2 and LaNi2Ge2 in 1 М KОН at a temperature of 22–48 °С was studied by polarization measurements and impedance spectroscopy. Polarization curves are the Tafel lines with a slope of 79–90 mV dec−1. It was shown that the Tafel slope of 80–90 mV dec−1 can be obtained within the framework of the Volmer–Heyrovsky mechanism and simultaneous occurrence of hydrogen absorption reaction with both Langmuir isotherm of hydrogen adsorption and logarithmic Temkin isotherm. The polarization and impedance data for the studied compounds were explained on the basis of the Volmer–Heyrovsky mechanism with parallel proceeding hydrogen absorption. The values of some rate constants (including the rate constants per unit real surface area) were estimated.