Reactive Sputtered Ir1−yNiyOx Electrocatalysts For The Oxygen Evolution Reaction in Alkaline Media

Abstract

One drawback of alkaline water electrolysis (AWE) is the sluggish oxygen evolution reaction (OER) kinetics at the anode of the electrolyser and improvement of the anode material is still a necessity. Various Ir1−yNiyOx electrocatalyst combinations were prepared by reactive sputtering and subjected to high-throughput electrochemical screening using a Au/SiO2 wafer. The best performing electrocatalysts were identified and subjected to single electrode electrochemical and physical characterisation using glassy carbon disk electrodes as the substrate. Rotating disk electrode (RDE) analysis included linear sweep voltammetry (LSV) before and after short term chronopotentiometry (CP). Energy dispersive X-ray spectroscopy and X-ray photo-electron spectroscopy (XPS) confirmed the controlled synthesis of thin film electrocatalysts by utilising reactive sputtering, and confirmed Ir dissolution which occurred during CP measurements. Overall, the Ir1−yNiyOx electrocatalyst combinations containing higher amounts of Ir (Ir92Ni8Ox, Ir68Ni32Ox and Ir62Ni38Ox) performed the best of the evaluated mixed metal oxide electrocatalysts. However, evident from this study was that excellent mass-specific activity (current per mass of noble metal) was not exhibited by the mixed metal oxides when compared to Ni.