Plasma Sprayed Raney Nickel Coatings for Hydrogen Production by Alkaline Water Electrolysis

Plasma sprayed NiAl and NiAlMo Electrodes were developed for hydrogen and oxygen evolution reaction due to their high activity in alkaline media and low cost. One of the most critical challenges is the poor resistance to electrochemical erosion leading to low durability. Therefore, the aim of this work was to understand the correlation between process parameters and coating quality and with that improve the electrode performance. Air plasma spraying was performed using NiAl and NiAlMo powders. Plasma velocity and temperature were measured with enthalpy probe whereas particle inflight velocity and temperature was measured by Accuraspray. Coatings were developed for conditions in which particles in-flight temperatures were comparable but in-flight velocities differed. Electrochemical tests were performed. The SEM and EDX results before and after the electrochemical test show that the coatings with higher velocity particles led to microstructure that enabled better activation of the electrodes and higher surface area for reactions.