Electrochemical performance of porous Ni_3Al electrodes for hydrogen evolution reaction

摘要

Porous Ni_3Al 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 Ni_3Al 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 spec-troscopy (EIS) techniques. It is found that the onset potential of porous N1_3AI 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 Ni_3Al electrode. The corrosion tests showed that the corrosion resistance of porous Ni_3Al electrode changed during the immersion process due to the formation of passive film layers.