The hydrogen evolution reaction on NIPx alloys

The hydrogen evolution reaction (HER) was studied on NIP, electrodes containing 15-27 at% P prepared by electrodeposition. The amount of P in the alloy varied with deposition potential. The activity of the electrodes was dependent on the P concentration, and the formation of a passive film. The P in the deposited Ni alters the reaction mechanisms for the HER significantly. This is probably caused by the absorption of hydrogen into the NiPx alloy. A potential step, from the cathodic to the anodic region, gave information about the diffusion of absorbed hydrogen, A correlation between the activity of the electrodes, and the amount of absorbed hydrogen was found the most active electrodes also absorbed the largest amount of hydrogen. (C) 2000 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.