(617ga) A Highly Active and Stable IrOx/SrIrO3 Catalyst for the Oxygen Evolution Reaction
AIChE Annual Meeting
Wednesday, November 16, 2016 - 6:00pm to 8:00pm
We present investigation of a novel water oxidation catalyst, IrOx/SrIrO3, which has demonstrated remarkable activity and stability in acidic electrolyte.3 Thin, crystalline films of SrIrO3 are deposited using pulsed laser deposition and the active catalyst is formed via Sr leaching from surface layers. This leaching process leaves behind IrOx layers which significantly outperform rutile IrO2 and RuO2, the only other OER catalysts to have reasonable stability and activity in acidic electrolyte. XPS and inductively coupled plasma results indicate leaching of Sr from the material surface during initial electrochemical testing in acidic electrolyte, which likely contribute to material restructuring at the surface and result in the activity increase observed over the first 2 hours of electrochemical testing. Additionally, the low surface roughness of these films allows activity normalization to the catalyst surface area (measured using atomic force microscopy) and reveals only 270 â?? 290 mV overpotential to reach 10 mA/cm2oxide_AFM during extended testing. Lastly, density functional theory calculations reveal possible surface structures that could be formed during Sr leaching, and suggest the formation of highly active surface layers with IrO3 or anatase IrO2 motifs.
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3. L. C. Seitz, C. F. Dickens, K. Nishio, Y. Hikita, J. Montoya, A. Doyle, C. Kirk, A. Vojvodic, H. Y. Hwang, J. K. Norskov and T. F. Jaramillo, In review., 2016.