Porous Antimony Tin Oxide with a Particle Assembly Structure as an IrO2 Support for an Efficient Oxygen Evolution Reaction in Proton-Exchange Membrane Water Electrolysis

Proton-exchange membrane water electrolysis (PEMWE) holds great promise for hydrogen production applications. However, the reliance of PEMWE membrane electrodes on high loadings of expensive iridium poses a significant barrier to their commercial viability. Therefore, the development of high-performance oxygen evolution catalysts with a low iridium content is of critical importance. In this research, a porous antimony tin oxide (ATO) conductive support with a particle assembly aggregate structure was fabricated by a carbon template removal method. ATO-supported IrO2 exhibits significantly improved oxygen evolution reaction (OER) activity, with a much lower overpotential compared to the unsupported IrO2 catalyst. Moreover, it achieves 1.8 V at 2 A cm–2 with an ultralow loading of iridium (0.3 mgIr cm–2) for the proton-exchange membrane electrolyzer. Characterization techniques and density functional theory calculations have elucidated that the enhanced performance is attributed to the porous morphology of ATO and the strong metal oxide–support interaction between IrO2 and the ATO support. These findings validate the practicality of conductive nanostructured antimony-tin-oxide-supported catalysts for PEMWE applications and offer a pathway for the design of low-Ir OER catalysts.