Asymmetric Ru–O–Co sites coupled adsorbate evolution and oxide pathway mechanisms for enhanced acidic water oxidation

The acidic OER is central to green hydrogen production but is constrained by the limited activity and stability of RuO₂-based catalysts, which suffer from the inherent scaling relationship of the AEM. Activating the more efficient OPM on RuO₂ has been impeded by the large Ru–Ru distance (>3.1 Å) that disfavors direct O–O coupling.

Here, we develop an interpenetrated RuO₂/Co₃O₄ heterostructure that overcomes this barrier. The asymmetric Ru–O–Co bridges at the interface, with a short Ru–Co distance (<2.4 Å), selectively trigger the OPM by enabling low-energy O–O coupling, while non-interface Ru–O–Ru and Co–O–Co sites follow the AEM. This spatial and functional synergy breaks the single-mechanism limit, accelerates deprotonation, and enhances the antioxidant capacity of Ru.

As a result, the catalyst achieves an overpotential of only 196 mV at 10 mA cm^-2 and 370 mV at 500 mA cm^-2, with a mass activity 7.1 times higher than commercial RuO₂ and operates steadily for over 100 h at 500 mA cm^-2. This work provides a general interfacial design strategy for activating complementary reaction pathways. The work titled “Asymmetric Ru–O–Co sites Coupled Adsorbate Evolution and Oxide Pathway Mechanisms for Enhanced Acidic Water Oxidation”, was published in Advanced Powder Materials (available online on 1 July 2026).