Hydrogen is not only a promising energy, but also widely used in inflammation treatment and sports training. The key to these applications is to obtain purity hydrogen conveniently. Water electrolysis provides a green and sustainable method for hydrogen production, but the urgent problem is to develop low-cost and efficient electrocatalysts. In this work, hierarchically porous NiS nanostructures, which the flocculent two-dimensional NiS is coated on the surface of NiS nanosheets, were successfully grown on nickel foam through a facile two-step hydrothermal reaction. The hierarchically porous NiS nanostructures has a large specific surface area can expose more active sites and facilitates desorption of bubbles. Moreover, the theoretical calculation indicated that the dimensional confinement effect of metallic NiS improves the carrier concentration and conductivity. Therefore, the hierarchically porous NiS nanostructures on nickel foam exhibited enhanced hydrogen evolution reaction and good catalytic stability. This work sheds some light on improving the catalytic performance of metallic compounds.
