The hydrogen evolution reaction on NiPx alloys

The hydrogen evolution reaction (HER) was studied on NiPx 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.