Electrochemical performance of porous Ni₃Al electrodes for hydrogen evolution reaction

Porous Ni₃Al intermetallic material with a mean pore diameter of around 1 μm was prepared by step sintering Ni and Al powder pressed compacts in vacuum furnace at 900 °C. The electrocatalytic activity of the as-fabricated porous Ni₃Al material as an electrode for hydrogen evolution reaction (HER) in alkaline solutions was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) techniques. It is found that the onset potential of porous Ni₃Al for HER shifted in the positive direction favoring hydrogen generation with lower overpotential, compared with foam Ni and dense Ni electrodes. Effects of electrolyte concentration and temperature on HER as well as the electrochemical stability in alkaline solution were investigated and the electrochemical activation energy was determined for the porous Ni ₃Al. The increased activity for HER was attributed to the high porosity, an increased electrochemical surface area and the nanostructure of porous Ni₃Al electrode. The corrosion tests showed that the corrosion resistance of porous Ni₃Al electrode changed during the immersion process due to the formation of passive film layers.