Local Oxygen Vacancy-Mediated Oxygen Exchange for Active and Durable Acidic Water Oxidation

Developing an active and durable acidic oxygen evolution reaction (OER) catalyst is vital for implementing a proton exchange membrane water electrolyzer (PEMWE) in sustainable hydrogen production. However, it remains dauntingly challenging to balance high activity and long-term stability under harsh acidic and oxidizing conditions. Herein, through developing the universal rare-earth participated pyrolysis-leaching approach, we customized the active and long lifespan pseudo-amorphous IrO_x with locally ordered rutile IrO₂ and unique defect sites (IrO_x-3Nd). IrO_x-3Nd achieved a low overpotential of 206 mV and long-term durability of 2200 h with a slow degradation rate of 0.009 mV  h^-1 at 10 mA cm^-2, and, more importantly, high efficiency in PEMWE (1.68 V at 1 A cm^-2 for 1000 h) for practical hydrogen production. Utilizing in situ characterizations and theoretical calculations, we found that lattice oxygen vacancies (O_v) and contracted Ir-O in locally ordered rutile IrO₂ induced the O_v-modulated lattice oxygen exchange process, wherein thermodynamically spontaneous occupation of surface hydroxyl groups on O_v and effective promotion of O─O coupling and lattice oxygen recovery accounted for enhanced activity and durability. This work underscores the importance of tailor-made local configuration in boosting activity and durability of OER catalyst and different insights into the promotion mechanism.