Two-step Preparation of Porous Nickel-sulfur Electrode for Hydrogen Evolution in Alkaline Water Electrolysis

This work reports the preparation of 3D porous nickel-sulfur electrode for hydrogen evolution reaction (HER). The construction of the 3D porous structure is achieved by hydrogen bubbles dynamic templates, prepared from Cu electrodeposition at high current density. Subsequently, a nickel-sulfur film is electrodeposited on the 3D porous copper structure. The nickel-sulfur film with high crystal Ni3S2 content is achieved only through controlling deposition current. And the relationship between crystal structure and deposition current has been revealed. The porous crystal Ni3S2 electrode is significantly active for HER with a lower onset overpotential and an additional negative potential leading to a rapid increase in the cathodic current. And the developed electrode shows a lower charge transfer resistance for HER, which takes both advantages of high intrinsic activity and large real surface area. Besides, the electrode shows a higher electrochemical stability during the long-term electrolysis test.