NiF₂ Microspheres Grown on Nickel Foam for Efficient Hydrogen Evolution in Both Acidic and Alkaline Media

It is of technological significance to construct efficient electrocatalysts for hydrogen production. Here, a novel composite based on NiF₂ microspheres in situ grown on nickel foam (NiF₂/NF) has been synthesized by a facile solvothermal procedure. Benefiting from the synergistic contribution of NiF₂ microspheres and NF substrate, the derived NiF₂/NF composite demonstrated excellent electrocatalytic performance for the hydrogen evolution reaction (HER) in both acidic and alkaline media. Specifically, it can deliver current densities of 10, 100, and 300 mA cm^-2 at low overpotentials of only 40, 134, and 195 mV in 0.5 M H₂SO₄ and 69, 132, and 175 mV in 1.0 M KOH. Furthermore, an alkaline electrolyzer assembled with NiF₂/NF as both the cathode and anode only required a low cell voltage of 1.57 V to drive the current density of 10 mA cm^-2 for overall water splitting. This work proposed a new way for developing wide-pH HER electrocatalysts with high performance.