Developing efficient and durable anode electrocatalysts is essential for translating proton exchange membrane water electrolysis (PEMWE) into practical hydrogen production. Here, we report an Mn2O3 supported RuO2 electrocatalyst featuring short-range-ordered RuO2 domains that synergistically combines high activity and durability for acidic oxygen evolution. Hydrothermal Ru deposition followed by calcination enables uniform RuO2 dispersion on Mn2O3, yielding edge-rich RuO2 domains with limited long-range crystallinity. Structural characterization shows that RuO2/Mn2O3 retained stable Ru speciation and an almost constant oxygen vacancy fraction after extended OER operation, consistent with suppressed anodic degradation. Operando spectroscopy captures the key *OOH and *OO intermediates, supporting an adsorbate evolution mechanism (AEM) under acidic conditions. Building on the identified AEM pathway and the stabilized catalyst structure, RuO2/Mn2O3 achieves an overpotential of 150 mV at 10 mA cm-2, a Tafel slope of 44.6 mV dec-1, and stable operation for >400 h in acidic electrolyte. In PEMWE tests, RuO2/Mn2O3 delivers 1.0 A cm-2 at 1.61 V and operates stably for 100 h at 200 mA cm-2, highlighting its promise for practical acidic water electrolysis.
Cui et al. (Mon,) studied this question.