Dynamic hydroxyl mediated charge buffering stabilizes high valence ruthenium edge sites for acidic water oxidation

High valence metal species are essential for driving electrocatalytic acidic water oxidation, but suffer from intrinsic thermodynamic instability. This activity-stability paradox is particularly severe for ruthenium-based catalysts, where highly active Ru(>IV) species are also precursors for rapid dissolution. Here we show that a cooperative host-guest architecture circumvents this trade-off through dynamic, hydroxyl-mediated charge buffering. By anchoring isolated ruthenium atoms at β-MnO2 edge sites, we demonstrate that host-derived surface hydroxyls govern both kinetics and robustness. These hydroxyls optimize intermediate binding to facilitate ideal O-O coupling, accelerating the reaction. Concurrently, the specific coordination environment allows the manganese host to reversibly accommodate excess oxidative charge, preventing irreversible structural degradation and ruthenium dissolution. The resulting Ru0.03Mn0.97O2 catalyst achieves a mass activity 223-fold higher than RuO2 and increases the stability number by three orders of magnitude. As an anode in a proton exchange membrane electrolyzer, it sustains an industrial-level current density of 1 A cm−2 for over 1000 h, comparing favorably to IrO2 while reducing precious metal usage by 80%. Highly active ruthenium-based catalysts for acidic water oxidation typically suffer from rapid dissolution. Here, the authors design a ruthenium-manganese host-guest architecture where surface hydroxyls buffer oxidative charge, enabling stable electrolysis at industrial currents.