Efficient and Stable Electrochemical Oxygen Evolution Reaction Catalysis with Ti-Based Electrodeposited Iridium Oxide Electrodes: The Influence of Thermal Treatment

Dimensional stable anodes (DSA) have shown exceptional performance in water electrolysis, but their high cost and scarcity raise concerns. Seeking more efficient utilization of Ir-based catalysts is crucial. This study investigates the catalytic performance and stability of Ti-based electrodeposited iridium oxide electrodes (e-IrOx/Ti) for the oxygen evolution reaction (OER) in acidic media, focusing on the impact of different temperature thermal treatments on their crystal structure, electronic structure, Raman spectroscopy, and cyclic voltammetry. The thermal treatment temperature influences the deposition layer, gradually transforming amorphous IrOx into rutile-type IrO2 with enhanced crystallinity. At 450°C, the deposition layer exhibits a mixed phase of Ir2O3 and IrO2, with Raman features suggesting an [IrO6]n edge-sharing polyhedra (with n ≥ 3) structure, leading to improved OER electrocatalytic performance. However, higher temperatures (≥550°C) result in the formation of K0.25IrO2 and decreased electrochemically active surface area. Accelerated lifetime testing reveals impressive stability and substantial service life for e-IrOx/Ti-450 electrodes. The dissolution of iridium in the OER reaction indicates a coupling of lattice oxygen and adsorbate evolution mechanisms for the electrocatalysis of e-IrOx/Ti. These findings offer valuable insights for designing efficient and stable OER catalysts.