Operando Grazing-Incidence XPDF of Iridium Oxide Thin Films under Reducing Conditions

A key durability challenge arises during on–off cycles, when hydrogen crossover can drive the anode to reducing potentials and trigger cathodic dissolution. Despite its importance, the structural response of IrOx under such conditions remains poorly understood. While oxidative regimes have been extensively studied, reducing environments present unresolved questions about short-range disorder, amorphous-to-crystalline transitions, and degradation pathways. Operando grazing-incidence X-ray pair distribution function (GI-XPDF) analysis provides the necessary surface sensitivity and resolution to capture these structural dynamics in thin films. Insights from such measurements are critical for establishing a mechanistic understanding of hydrogen crossover-induced degradation and for informing strategies to design more stable electrolyser catalysts.