Hydride Effect on the Kinetics of the Hydrogen Evolution Reaction on Nickel Cathodes in Alkaline Media

The time-dependent hydrogen evolution reaction (HER) on Ni electrodes shows a large increase in electrode over-potential with time. This is ascribed to hydride formation at active Ni cathode surfaces. Hydride formation was detected by x-ray diffraction, morphological changes at the electrode surfaces, and resulting changes in secondary electron emissivities. Nickel electrodes annealed for 2 h in an argon atmosphere at 1000 o C after HER did not show x-ray lines assigned to hydride