Deactivation Mechanisms of Atmospheric Plasma Spraying Raney Nickel Electrodes

Major current research trends in alkaline electrolysis are targeted toward improving efficiency, extending the durability and decreasing the price of the electrolyzer units. The novel atmospheric plasma spraying (APS) production method for Raney nickel coatings demonstrated good efficiency for the hydrogen evolution reaction (HER). The research work performed focused on the investigation of the degradation/deactivation mechanisms of these APS electrodes. The formation of hydrides was recognized as a key contributor toward cathode deactivation and to prevent it, in-situ activation in the electrolyte as well as hydrides oxidation, through controlled switching of the cell potential were carried out. Both techniques showed some effect in suppressing the deactivation process but failed to eliminate it completely. The APS Raney nickel cathodes also presented good stability for variable load operations during the cycling.