Heterojunction coatings of non-precious metals prepared by plasma spray for water splitting

As one of the most promising processes to produce hydrogen, the application of water splitting suffers from the poor stability of anode catalyst. This work was proposed to develop anode coatings with excellent durability and reasonable performance by constructing heterojunction between Nickel and spinel oxides. The addition of spinel introduced numerous oxygen vacancies which accelerated the adsorption of OH-, and the Ni skeleton endowed the coating with high electrical conduction. Air plasma spray was applied to obtain coatings with controlled composition. The concentration of oxygen vacancy, the surface area, the phase composition, and the electrochemical performance were characterized to estimate the spinel doping effect. Finally, a model was illustrated to understand the effect of heterojunction on OER. This work shows an efficient method to prepare OER electrodes with controllable costs for commercial water-splitting applications.