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

• Published in: Journal of the Electrochemical Society Vol. 139; no. 1; pp. 98 - 105
• Main Authors: Soares, D. M., Teschke, O., Torriani, I.
• Format: Journal Article
• Language: English
• Published: 01.01.1992
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.2069207

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 Ar atmosphere at 1000 deg C after HER did not show X-ray lines assigned to hydride. On the other hand, hard Ni electrodes (180 HV5/30) show high overvoltages and hydride X-ray diffraction lines after HER. By taking the variation of the Ni electronic density of state following H sorption into account, the increase in Ni overpotential after a few hours of HER can be explained.