Hydrogen evolution activity of Ni–Mo coating electrodeposited under magnetic field control

Enhancement of catalytic activity of Ni–Mo alloy for hydrogen evolution reaction (HER) has been observed when the alloy is electrodeposited under magnetic field, B control. Using cyclic voltammetry at low scan rate and electrochemical impedance spectroscopy (EIS) measurements, the significant modification of the activity of the alloy has been characterized in acidic and in basic water at 25 °C and in 33% NaOH solution at 85 °C. For the deposit obtained with B, the polarization curves show high current densities values (about 50% higher then without B), low ohmic drop and overpotential shift to noble way more then 100 mV. EIS measurements show a low polarization resistance and a high double layer capacitance for the alloy deposited under magnetic field control. In basic media, with or without B, the EIS measurements exhibit a supplementary inductive type relaxation.