The kinetics of the hydrogen evolution reaction on CeM2Ge2 (M = Fe, Co, Ni) electrodes in alkaline solutions

Abstract

The kinetics of hydrogen evolution reaction on the intermetallic compounds CeM2Ge2 (M = Fe, Co, Ni) in 0.5–2.0 M KOH solutions were studied using polarization measurements and electrochemical impedance spectroscopy. For 1 M KOH, the Tafel constants vary in the intervals: а = 0.46–0.57 V; b = 0.082–0.096 V. The catalytic activity in the hydrogen evolution reaction increases in the sequence CeFe2Ge2 – CeNi2Ge2 – CeCo2Ge2. The cathodic process was shown to be the combination of the hydrogen evolution reaction and hydrogen absorption reaction; the reaction of H2 evolution proceeds through the Volmer – Heyrovsky mechanism with the rate-determining Heyrovsky reaction; the Langmuir isotherm holds for the adsorption of atomic hydrogen.