Non‐Planar Chlorine‐Coordinated Activation of Triatomic Ruthenium Sites for Efficient Oxygen Reduction

ABSTRACT The intrinsic electronic structure of Ru‐based catalysts exhibits strong adsorption of oxygen‐containing intermediates, which runs counter to the adsorption requirements of the oxygen reduction reaction (ORR), limiting their ability to achieve high activity. In this study, we employed a spatial confinement‐pyrolysis strategy to develop a chlorine‐doped triatomic Ru catalyst (Ru 3 ClNC), whose active center consists of a Ru 3 ON 6 Cl unit stabilized by both Ru─Ru bonds and Ru─N/O/Cl coordination bonds. Ru 3 ClNC delivers a high alkaline half‐wave potential ( E 1/2 ) of 0.90 V and an acidic E 1/2 of 0.79 V; the assembled zinc‐air battery demonstrates excellent performance in terms of energy density and durability. In situ experiments and theoretical calculations have demonstrated the superiority of Ru 3 ON 6 Cl as the electrocatalytic ORR active site. The non‐planar coordination effects and electronic effects of the Cl atom, in synergy with the triatomic site, disrupt the high symmetry, trigger charge redistribution, and significantly optimize the localized electron density at the active site. Importantly, the rearranged electronic structure breaks the linear scaling relationship in the d ‐band, enabling the catalyst to simultaneously optimize the rate‐determining step of Ru 3 NC and OH * desorption, thereby enhancing reaction kinetics. This provides a new design concept for Ru‐based catalysts to overcome the thermodynamic limitations and thereby improve the ORR activity.