Lim, Ahyoun Ham, Kahyun Quast, Thomas Lee, Suji Tesch, Marc F. Czioska, Steffen Ramermann, Daniela Hetaba, Walid Schuhmann, Wolfgang Grunwaldt, Jan-Dierk Cho, Sung Ki Park, Hee-Young Jang, Jong Hyun Ahn, Sang Hyun Spanos, Ioannis Park, Hyun S. 2025-04-25T06:31:01Z 2025-04-25T06:31:01Z 2025-04-25 2025-04 2155-5435 https://pubs.kist.re.kr/handle/201004/152313 As the demand for hydrogen production increases, the economic viability and stability of Ir-based catalysts are crucial in proton exchange membrane water electrolysis (PEMWE). In this study, stable low-loading Ir electrodes (0.2 mg(Ir) cm(-2)) with nanometer-thick electrodeposited layers are prepared on Pt-deposited Ti felts. State-of-the-art techniques, such as operando quick extended X-ray absorption fine structure spectroscopy (QEXAFS) and identical-location transmission electron microscopy (IL-TEM) employing an ultramicroelectrode (UME), were used to demonstrate the structural transformation of surface Ir during oxygen evolution reaction (OER) and the pivotal role of catalyst film thickness control on the self-terminated growth of crystalline IrO2, which enhances catalyst stability. A lack of a stabilizing IrO2 sublayer in thin electrodeposited Ir layers (<10 nm) leads to a fully amorphous catalyst structure, directly impacting its durability. The obtained Ir/IrO2/IrOx electrodes achieve catalytic activities of 1.8-12 A mg(-1) at 1.6 V-Cell while maintaining a degradation rate of 8.7 mu V h(-1) @ 2 A cm(-2) during accelerated stress tests (>1000 h) and 1.6 times greater stability (corresponding to a lifespan of 55,000 h) and 3.6 times higher mass activity compared to commercial Ir oxide electrodes. English American Chemical Society Limited Surface Oxide Growth as a Prerequisite for Stabilizing Low-Loading Iridium Electrodes for PEM Water Electrolysis Article 10.1021/acscatal.4c07864 1 ACS Catalysis, v.15, no.8, pp.6098 - 6113 ACS Catalysis 15 8 6098 6113 Y scie scopus 001457312600001 2-s2.0-105001493741 Chemistry, Physical Chemistry Article OXYGEN EVOLUTION REACTION RAY-ABSORPTION SPECTROSCOPY DEGRADATION MECHANISMS HIGH-PERFORMANCE MEMBRANE CATALYST OXIDATION ELECTROCATALYSTS TRANSMISSION DISSOLUTION proton exchange membrane water electrolysis oxygenevolution reaction low-loading iridium electrode operando X-ray absorption spectroscopy porous transportelectrode