Electrochemical performance of porous Ni–Cr–Mo–Cu alloys for hydrogen evolution reactions in alkali solution

Porous Ni–Cr–Mo–Cu alloys were fabricated by an activation reaction sintering technique with Ni, Cr, Mo, and Cu element powders as raw materials. The phase constitutes, morphology, and hydrogen evolution mechanism of the electrode were characterized by x-ray diffraction, scanning electron microscopy, and x-ray photoelectron spectroscopy. The electrochemical characterization for hydrogen evolution reaction (HER) was investigated by cyclic voltammetry curves, electrochemical impedance spectroscopy, and linear sweep voltammetry. Different parameters, including Cr content, temperature, and solution concentration that affected electrocatalytic activity for HER were also considered. The results illustrated that porous Ni–Cr–Mo–Cu electrodes possessed excellent hydrogen evolution performance, and the Cr content within a certain range 15 ∼ 25 wt% improved hydrogen evolution catalytic activity. The surface roughness R _f of porous 60 wt%Ni-25 wt%Cr-10 wt%Mo-5 wt%Cu alloy electrodes was 8718.4, and the electrochemical activation energy is determined to be 7.46 kJ∙mol⁻¹, compared with 53.44 kJ∙mol⁻¹ for porous 70 wt%Ni-15 wt%Cr-10 wt%Mo-5 wt%Cu alloy electrodes. (paper)