Electrodeposited Ni-P electrodes: An effect of amorphous structure on the electrochemical behavior and electrocatalytic activity in the hydrogen oxidation reaction in alkaline media

Glassy carbon supported Ni/GC and amorphous Ni-P/GC electrodes were prepared by potentiostatic electrodeposition. The catalysts have been characterized by X-ray powder diffraction, transmission and scanning electron microscopy, and cyclic voltammetry. Particular attention has been paid to the influence of electrochemical oxidation on the electrochemical behavior of Ni-P/GC and Ni/GC electrodes in alkaline media as well as the activity of these electrodes in the hydrogen oxidation reaction (HOR). It was found that the oxidation treatment changes the properties of Ni/GC electrode due to the formation of active Ni/NiOx surface sites, while insignificantly affecting the performance of Ni-P/GC sample. The unordinary behavior of electrodeposited Ni-P/GC samples is tentatively attributed to their amorphous structure and the formation of nickel phosphate under high anodic potentials, which prevents the formation of irreversible Ni oxides.