ScholarWorks@중앙대학교

초록

Low-loading iridium (Ir) catalysts hold great promise for the acidic oxygen evolution reaction (OER) due to their typically high Ir utilization and reduced cost. However, their practical application is limited by poor stability under the harsh acidic oxidative conditions of proton exchange membrane (PEM) water electrolysis. Here, a controlled structural transformation strategy is presented that converts an unstable LiCoO2-supported Ir single-atom catalyst (Ir-LiCoO2) into a corrosion-resistant Co3O4-supported IrOx nanocluster catalyst (IrOx/Co3O4), significantly enhancing catalyst durability. Strong catalyst-support interactions between IrOx and Co3O4 facilitate charge transfer, thereby stabilizing the IrOx nanoclusters against leaching and optimizing the electronic structure of the Ir active sites. As a result, IrOx/Co3O4 exhibits substantially enhanced OER performance compared to Ir-LiCoO2, achieving excellent operational stability over 1200 h and a low overpotential of approximate to 233 mV at 10 mA cm-2 in 0.5 m H2SO4. This superior performance is further validated in PEM electrolyzers, confirming its practical applicability. Furthermore, theoretical calculations reveal that Ir sites in IrOx/Co3O4 exhibit higher dissolution potentials and improve charge transfer capabilities with OER intermediates compare to those in Ir-LiCoO2 and IrO2, which effectively suppresses Ir leaching and lowers the energy barrier of the potential-determining step.

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