NiMo–NiCu\nInexpensive Composite with High Activity\nfor Hydrogen Evolution Reaction

Abstract

In\nthis work, the effect of copper addition on NiMo coating is\nevaluated in regard to the hydrogen evolution reaction (HER). NiMo\nand NiMo–NiCu composites are prepared by a simple coelectrodeposition\nprocess. The effect of Cu on deposit characters were tested by varying\nit in the range of 0.06–0.20 molar ratio. Copper addition promotes\nthe growth of a new crystalline phase: NiCu. Also, the copper addition\nchanged the composite surface. NiMo–NiCu_0.12 shows\na surface roughness 30 times higher than the NiMo material. NiMo–NiCu\nmaterials present higher activity toward HER, larger electroactive\narea, and higher stability in continuous water electrolysis than NiMo\ncatalysts, as demonstrated by Tafel curves, electrochemical impedance\nspectroscopy measurements, and polarization tests. The combination\nof the large electroactive area due to the copper addition, the synergism\nbetween Ni–Mo, and the presence of Ni and Mo oxides on the\nsurface results in catalyst with excellent features for HER application.