An Electrolyte Additive Strategy for Enhancing Water-Splitting Hydrogen Production of Nickel-Based Electrodes

Sustainable water electrolysis has emerged as a future technology for producing green hydrogen. The general approach to improving water-splitting hydrogen production is to develop novel electrode materials. In this work, we reported an orthogonal approach, namely, regulating the electrolyte components. As a proof of concept, Na2S additive was introduced to the electrolytes to enhance the water-splitting performance of Ni-based electrodes. Specifically, a tiny amount of Na2S (50 mM) was employed as an electrolyte additive to reduce the hydrogen evolution overpotential of the Ni(OH)2 electrode from 262 to 193 mV at 10 mA cm-2. In situ Raman studies unveiled the formation of the NiS active phase and the S-H bond during electrocatalysis, which were responsible for such a performance improvement. Moreover, such an electrolyte additive strategy also showed its success in other Ni-based materials such as metallic Ni foam, other electrolytes such as saline water, and other catalytic reaction systems such as oxygen evolution.