Dynamic hydroxyl mediated charge buffering stabilizes high valence ruthenium edge sites for acidic water oxidation.
basic_science · Level V
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- Record sourced from PubMed, PMID 42303636.
- Also identified by DOI 10.1038/s41467-026-74540-9.
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Abstract
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-MnO<sub>2</sub> 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 Ru<sub>0.03</sub>Mn<sub>0.97</sub>O<sub>2</sub> catalyst achieves a mass activity 223-fold higher than RuO<sub>2</sub> 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<sup>-2</sup> for over 1000 h, comparing favorably to IrO<sub>2</sub> while reducing precious metal usage by 80%.