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 paramete...