Impact of different metallic forms of nickel on hydrogen evolution reaction

Abstract

In this work, we show the influence of strain in two different forms (plate and foil) of nickel for hydrogen evolution reaction (HER) in alkaline solution and 3.5% NaCl aqueous solution. The presence of tensile strain in nickel foil lowers the overpotential by about 10 mV to reach a current density of 10 mA cm−2 and improves the reaction kinetics of HER in alkaline solution. The Tafel slope showed a significant change in the strained nickel (i.e., in Ni foil) which gave a value of 111 mV dec−1 compared to unstrained nickel (Ni plate) which was found to be 151 mV dec−1, thus indicating a change in reaction mechanism. Compared to alkaline solution, the effect of strain becomes less pronounced in NaCl solution which can be attributed to Cl− adsorption on the electrode, thereby reducing its catalytic activity.