Copper-Doped NiCo2S4 Nanosheets Grown on Ni Foam Efficient Hydrogen Evolution Catalyst in Alkaline Solution

The development of economical, efficient and stable electrocatalysts for hydrogen evolution reaction (HER) with non-precious metals remains challenging. In this work, we have prepared Cu-doped NiCo 2 S 4 nanosheets grown on nickel foam that can serve as excellent electrocatalysts for HER in alkaline solutions (Cu-NiCo 2 S 4 /NF). The good electrocatalytic properties and excellent stability of the pristine NiCo 2 S 4 were achieved by changing its morphology through a simple Cu doping strategy. The optimum doping ratio for the Cu-NiCo 2 S 4 /NF catalyst in the HER requires an overpotential of only 155 mV to achieve a current density of 10 mA cm −2 and can operate stably for at least 12 h. This is mainly due to the fact that the doping of copper optimizes the electronic structure of the NiCo 2 S 4 /NF surface, providing more catalytically active sites and thus facilitating the effective release of hydrogen. In addition, the electrocatalytic activity of the Cu-NiCo 2 S 4 /NF material exceeds that of most reported noble metal-free catalysts, which also provides a new strategy for the preparation of NiCo 2 S 4 -based hydrolysis catalysts.