Electrodeposition of Ni‐P alloy from deep eutectic solvent and its electrocatalytic activity toward hydrogen evolution reaction

Abstract

AbstractNi‐P alloys have been successfully electrodeposited in the choline chloride and ethylene glycol with a molar proportion of 1:2(CE) electrolyte and their activities toward hydrogen evolution reaction (HER) have been also evaluated. The electrodeposition of Ni‐P alloy follows a co‐deposition process, and the bulk growth of which depends on an instantaneous nucleation under diffusion control. The morphologies of Ni‐P alloys are significantly influenced by the P content, and low P content can lead to a smooth surface. As expected, Ni‐9.0 wt.% P alloy shows an impressive HER catalytic performance with a Tafel slope (b) of 72.9 mV dec−1 and an overpotential of 105 mV at 50 mA, in agreement with its large ECSA (Cdl = 3.25 mF cm−2) and small interface charge‐transfer resistance. More interestingly, Ni‐9.0 wt.% P alloy exhibits a sustainable catalytic activity toward HER after 1000 cycling test with a tiny potential decline of ~10 mV at 100 mA cm−2. Such a striking HER activity of Ni‐9.0 wt.% P alloy can be attributed to the synergistic effect among the induced active sites from lattice contraction, negatively charged P incorporation, and a mixed nanometre crystal and amorphous structure. Thus, Ni‐P alloy electrodeposited in a CE‐based electrolyte can be used as a promising electrode material with high HER activity in alkaline solutions for hydrogen production.