Electrodeposition of Ni, Ni-W and Ni-Co-W coatings and investigation of hydrogen production efficiency

In this research, Ni, Ni-W and Ni-Co-W coatings were deposited on the steel substrate. The surface exposed to plating was 2 square centimeters. The coatings were deposited by pulsed electrodeposition method and under different conditions. The current density for electrodeposition was 0.025 A/cm2. The electrodepositon performed at 25 and 50 centigrade temperature. The results showed that Ni-Co-W ternary coating which was deposited at ambient temperature shows better electrocatalytic activity than other coatings for hydrogen evolution reaction (HER) in alkaline environment. Linear sweep voltammetry measurements and electrochemical impedance spectroscopy in 0.1 M NaOH showed that the best coating was Ni-Co-W (at ambient temperature) and had a lower potential (1.3031 mV). The results showed that electrocatalytic activity of coatings increased with decreasing of temperature of electrolytic bath. The surface morphology and chemical composition of the coatings were investigated by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The surface morphology of coatings was spherical and platelet.