Kinetics of the Hydrogen Evolution Reaction at Various Zr‐Based Loves‐Phase Hydrogen‐Storage Alloy Electrodes

The kinetics of the hydrogen evolution reaction at various Zr‐based laves‐phase hydrogen‐storage alloy electrodes was investigated by measuring an overpotential‐decay curve immediately after the interruption of an applied constant current. The measured overpotential was divided into two partial overpotentials corresponding to the elementary reactions, i.e. , the Volmer (discharge) and Tafel (combination) reactions. The ratio of exchange current density for the Volmer (discharge) reaction to that for the Tafel (combination) reaction increased with increasing unit‐cell volume of the hydrogen‐storage alloys used, suggesting that the Tafel (combination) reaction is effectively suppressed.