Unlocking the synergistic effect of heterostructures and oxygen vacancies to regulate ruthenium sites for durable oxygen evolution in acidic conditions

Ruthenium (Ru)-based catalysts are promising for acidic oxygen evolution reaction (OER) in proton-exchange membrane water electrolysis (PEMWE), yet they suffer from severe corrosion and over-oxidation. Herein, we synergistically integrated Ru/RuO 2 heterostructures with pre-introduced oxygen vacancies (O V ) within a porous carbon (PC) framework derived from ZIF-8. Theoretical calculations and mechanistic spectroscopy confirmed that the heterointerfaces and O V regulate electronic distribution, lower Ru oxidation state, and optimize intermediate adsorption, thereby switching the reaction pathway from detrimental lattice oxygen mechanism to favorable adsorbate evolution mechanism. The resulting O V -Ru/RuO 2 @PC catalyst exhibits a low overpotential of 234 mV at 10 mA cm −2 and ultra-long stability exceeding 1000 h. Assembled in PEMWE, it delivers 1 A cm −2  at 1.77 V with a negligible degradation rate of 59 μV h −1 over 500 h, surpassing commercial RuO 2 . This work establishes a biomimetically inspired strategy to address the activity-stability trade-off of Ru-based OER catalysts for practical PEMWE.