Iridium- and oxophilic-manganese-doped TiO2 nanowires enable lattice oxygen activation and regeneration for efficient acidic water oxidation

Activating lattice oxygen (O L ) redox offers a promising route for developing effective oxygen evolution reaction (OER) electrocatalysts for proton exchange membrane water electrolysis (PEMWE). However, achieving both efficient activation and rapid regeneration of O L to ensure high activity and durability for OER remains challenging. Herein, Ir-Mn-doped TiO 2 nanowires (Ir-Mn/TiO 2 NWs) were synthesized via a simple hydrothermal and annealing methods. By leveraging the oxophilicity and Jahn-Teller effect of Mn(Ⅲ), stable and controllable oxygen vacancies are induced. The electronic structure is modulated to enhance Ir-O covalency, thereby activating O L and triggering a highly active lattice oxygen-mediated pathway. On the other hand, local charge redistribution is promoted, which facilitates thermodynamically favorable adsorption of surface *OH to enable rapid O L regeneration, preventing oxygen vacancy accumulation and stabilizing active Ir sites. Consequently, the optimized catalyst exhibits a low overpotential of 179 mV at 10 mA cm −2 , and good stability exceeding 1000 h at 100 mA cm −2 . Notably, when applied in PEMWE it demonstrates a low cell voltage (1.65 V, 1 A cm −2 ) and outstanding long-term durability (0.039 mV h −1 , 1500 h@1 A cm −2 ). This study provides a valid strategy for designing efficient and stable OER catalysts for PEMWE applications.