Constructing a Localized OH Buffer Motif to Improve the Alkaline Hydroxide Reaction over Ru Clusters

Abstract Developing Ru‐based catalysts with high activity and stability for the alkaline hydrogen oxidation reaction (HOR) to replace precious Pt is essential for the practical application of anion exchange membrane fuel cells (AEMFCs) and Ni‐H batteries. However, the hydroxyl group (OH), as one of the reactants of HOR, will be over‐adsorbed on the Ru surface, resulting in its oxidative deactivation. Here, a new strategy is presented to overcome these limitations by anchoring a localized OH buffer motif on the Ru surface, thereby promoting the alkaline HOR. Density functional theory calculations, in situ X‐ray absorption spectroscopy, and in situ attenuated total reflection‐infrared spectroscopy demonstrate that the OH buffer motif on the Ru surface can effectively extract OH species from the Ru surface to expose active Ru sites, while creating a localized high OH concentration environment to facilitate the kinetics of the rate‐determining step of the HOR process. This OH buffer mechanism improves the overall performance of alkaline HOR. Remarkably, it results in a record 32.1‐fold increase in kinetic mass activity and a 2.2‐fold increase in exchange current density compared to the pure Ru surface, significantly improving the performance of AEMFCs and Ni‐H batteries.