Interfacial carbon vacancy stabilized ruthenium oxide for efficient acidic oxygen evolution.

Advancement of proton exchange membrane water electrolyzers (PEMWEs) requires the development of high-performance catalysts for the anode acidic oxygen evolution reaction (OER), particularly RuOx-based catalysts. However, practical applications have been hindered by poor stability, resulting from excessive oxygen leaching and severe RuOx agglomeration. Here, we report an interfacial carbon vacancy confined strategy to stabilize active RuOx nanoparticles on titanium carbide supports (TiCx), delivering a mass activity of 1095.4 A g-1Ru at 1.47 V vs. the reversible hydrogen electrode (RHE), outperforming most reported RuOx-based electrocatalysts, while maintaining stable operation over 600 h at 10 mA cm-2. In-situ spectroscopic analyses, combined with theoretical calculations, reveal that the TiCx support reduces the overlap between Ru 4d and O 2p orbitals, thereby suppressing lattice oxygen reactivity and inhibiting the involvement of the detrimental lattice oxygen mechanism. Identical location transmission electron microscopy and molecular dynamics simulation demonstrate that carbon vacancies induce strong catalyst-support interactions, effectively maintaining well-dispersed RuOx nanoparticles without agglomeration during the OER. Importantly, the assembled PEMWE employing the as-prepared RuOx/TiCx catalyst achieves a low cell voltage of 1.61 V at 1 A cm-2 and high durability for over 200 h at 200 mA cm-2. This interfacial vacancy confinement strategy provides an effective approach for designing highly durable electrocatalysts for practical applications.