Abstract
To achieve a sustainable and environmentally benign energy paradigm shift, the utilization of renewable energy sources through water electrolysis, especially proton exchange membrane water electrolysis (PEMWE), emerges as a promising solution. Accordingly, enhancing catalytic activity and stability of the anode catalyst (IrO2), which constitutes a significant portion of the cost of PEMWE, is crucial for its practical commercialization. Notably, recent research has shed light on the pivotal role of Ir-O bond distance in IrO2-based electrocatatlysts, where doping or composite formation with foreign atoms influences oxygen evolution reaction (OER) activity and stability. Therefore, understanding these Ir-O bond distance is crucial to effectively manipulate the OER activity and stability. Herein, we developed a hybrid-phase of Ti-added IrO2 electrocatalyst, demonstrating remarkable OER activity of 233.5 mV at 10 mA/cm2 and stability for over 25 h through fundamental insights into asymmetric interatomic interactions induced by Ti adoption. Our findings reveal that optimizing the multi-phase evolution by introducing Ti into IrO2 yields compressive strains in IrO2 motifs reducing the Ir-O bond distance effectively increase the OER activity. However, In-situ X-ray absorption spectroscopy (XAS) analysis further confirms that the longer Ir-O bond distance at 1.5 V (vs. RHE) of hybrid-phase of Ti-added IrO2 indicates the facile formation of –OOH* intermediates, offering outstanding OER stability by suppressing Ir dissolution. These advancements represent a breakthrough in enhancing the OER activity and stability of IrO2, marking a significant milestone in advancing transformative energy shifts toward sustainable and environmentally integral renewable sources.
Published Version
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