Controllable oxygen vacancy induced Ru–O constraint ability for enhanced water oxidation

Ruthenium dioxide (RuO 2 ) is one of the best-known electrocatalysts for the anodic oxygen evolution reaction (OER) in water electrolysis, while the poor stability of pristine RuO 2 greatly affects its application. Here, we report a general “plasma bombing” strategy to engineer the vacancy density in metal oxides, effectively overcoming the activity-stability trade-off for OER. The oxygen vacancy (Ov) density can be precisely controlled by adjusting the plasma bombing parameters, thereby modulating the crystallinity, structural integrity, and the strength of Ru–O bonds. Accordingly, an appropriate amount of Ov endows the catalyst with the necessary Ru–O constraint ability without affecting the structural rigidity of RuO 2 , which corresponds to a plasma bombing power of 300 W. The enhanced constraint ability of Ru–O bond suppresses reactive oxygen participation and prevents the dissolution of Ru active sites, thus reinforcing catalytic stability. Mechanistic studies reveal that Ov density modulation strengthens the Ru–O bond, thereby restricting lattice oxygen mobility. This further shifts the reaction mechanism from the lattice oxygen oxidation mechanism to the adsorbate evolution mechanism, while preventing dissolution of coordinatively unsaturated Ru sites (Ru cus ). The optimized Ov-rich ruthenium dioxide (Ov-RuO 2 ) catalyst (22.23 % Ov density) exhibits robust OER stability exceeding 2000 h (degradation rate is 27 μV h −1 ) in alkaline electrolytes. Moreover, this proposed “plasma bombing” strategy is universally applicable to iridium oxide, cobalt oxide trioxide, and manganese oxide through the similar mechanism of M − O constraint ability.