Studies of the Hydrogen Evolution Reaction on Raney Nickel–Molybdenum Electrodes

The hydrogen evolution reaction was studied in 1 M KOH at 25 °C on two types of electrodes:(i) pressed powders of Ni or NiMo with Al, heated at 700 °C; (ii) Ni—Al—Mo powders deposited by vacuum plasma spraying. These materials were treated with alkaline solution to leach out aluminum. Very active and stable Raney nickel—molybdenum electrodes were obtained from Al rich alloys. Adding molybdenum significantly improved catalytic activity. Electrochemical impedance spectroscopy was used to determine the apparent and intrinsic activities. Different ac models were tested and the appropriate one was selected. Intrinsic activities of these electrodes are smaller or equal to that of polycrystalline Ni and the origin of high apparent activities is related to the increase in real surface area.