Evaluation of Raney nickel electrodes prepared by atmospheric plasma spraying for alkaline water electrolysers

The work describes the evaluation of Raney nickel electrodes prepared by the technique of atmospheric plasma spraying (APS). The APS Raney nickel layers of 30 μm, 100 μm and 300 μm thicknesses were characterised prior to and post-chemical activation by SEM. Following further electrochemical activation, the performance of these layers towards hydrogen evolution reaction (HER) were evaluated using potentiodynamic Tafel analysis and electrochemical impedance spectroscopy (EIS) in 30% KOH solutions over the temperature range 30 °C-80 °C. Large surface area increases, in relation to smooth nickel, were obtained for these layers following activation and these were also confirmed from cyclic voltammetry measurements. The analysis of the data indicated that of the 3 thicknesses examined, the best electrocatalytic activity towards HER was obtained for 100 μm sample, with an efficiency (based on the Higher Heating Value for H2) equal to 96% at a current density of 300 mA cm−2 and temperature of 70 °C.