Nucleation and growth mechanisms of an electrodeposited Ni–Se–Cu coating on nickel foam

Electrocatalysts for water splitting have been widely explored among recent years. In this study, nickel–selenium–copper (Ni–Se–Cu) coating was synthesized on nickel foam through potentiostatic electrodeposition. The electrochemical kinetics and nucleation mechanisms of the deposition were investigated, and the diffusion coefficient D from different deposition potentials and temperatures was calculated. Results reveal that the electrodeposition of Ni–Se–Cu follows an instantaneous nucleation and diffusion-controlled three-dimensional (3D) growth mechanism. Deposition potential and bath temperature slightly effect the nucleation mechanism of electrodeposition. The apparent activation energy Ea of the hydrogen evolution reaction (HER) in 1.0 M KOH electrolyte of Ni–Se–Cu is 21.1 kJ·mol−1, which is lower than that of Ni–Se (37.7 kJ·mol−1). The majority phase formed by nickel and selenium is Ni3Se2, and a Ni(Cu) solid solution forms after the incorporation of Cu atoms into a Ni lattice.