Electrochemical Deposition and Characterization of Ni and NiCu Coatings for Hydrogen Evolution Reaction

Resumo

In this study, NiCu alloy coatings were electrochemically deposited on a copper electrode (Cu/NiCu). The effects of Ni/Cu mole ratio in the electrolyte and the current density on alloy composition and morphology as well as on the hydrogen evolution reaction (HER) in the alkaline solution for electrodeposited NiCu were investigated. The electrocatalytic activity of the fabricated NiCu alloys for the HER in alkaline solutions at 30°C was investigated by the polarization measurements and electrochemical impedance spectroscopy techniques. The morphology and chemical composition of the electrodeposited NiCu were characterized by scanning electron microscopy and atomic absorption spectroscopy. It was found that a NiCu electrode with copper content of ca. 14 wt % and a large surface area show a high electrocatalytic activity for the HER. The experiments were carried out in a bath with a pH of 8.0, Ni/Cu mol ratio of 1/20 and 0.2 M sodium citrate concentration at a current density of 50 mA cm^–2. The fabricated alloys stability was tested by polarization measurements after different anodic and cathodic treatments in 1 M NaOH solution. Moreover, the corrosion behavior of Cu/Ni and Cu/NiCu electrodes at an open circuit potential was also investigated and their corrosion resistances were compared.