Electrocatalytic activity of Ni–Fe–M (M = Cr, Mn, Cu) sintered electrodes for hydrogen evolution reaction in alkaline solution

Ternary Ni60Fe30M10 (M = Cr, Mn, Cu) sintered alloys have been characterized by means of microstructural and electrochemical techniques in view of their possible applications as electrocatalytic materials for hydrogen evolution reaction (HER). Well-mixed powders of nickel, iron and copper, manganese, or chromium were pressed together under high pressure at room temperature and then sintered in vacuum at high temperature. The surface morphology of the alloys was examined by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDXS). The electrochemical efficiency of the electrodes has been studied on the basis of electrochemical data obtained from steady-state polarization and electrochemical impedance spectroscopy (EIS) techniques in 1 M NaOH solution at 298 K. The results were compared with those obtained on binary Ni60Fe40 sintered alloy. The overall experimental data indicate that alloying Ni–Fe with Cr, Mn and Cu leads to an increase of electrocatalytic activity in hydrogen evolution with respect to the Ni60Fe40 electrode. High catalytic efficiencies were achieved on Ni60Fe30Mn10 and Ni60Fe30Cr10 electrodes, the latter being the best electrocatalyst for the HER.