Atomically Ru‐Doped Co ₃ O ₄ With Asymmetric Ru–O–Co Sites for High‐Performance Chlorine Evolution

ABSTRACT Chlorine production remains foundational to chemical manufacturing, yet its electrochemical generation is hindered by sluggish kinetics and unfavorable intermediate adsorption−desorption dynamics. Here, we fabricate atomically Ru‐doped Co ₃ O ₄ featuring asymmetric Ru–O–Co bridge sites, in which isolated Ru atoms are incorporated into the Co ₃ O ₄ spinel lattice to regulate the local coordination environment and electronic structure. In situ spectroscopic characterizations combined with first‐principles calculations reveal that Ru substitution disrupts the rigid symmetric Co–O–Co configuration and weakens the excessively strong Co–Cl interaction. The relatively weak Ru 4p–O 2p coupling endows Ru sites with abundant accessible vacant orbitals, favoring the formation of labile Ru–Cl species and enabling rapid and reversible Cl adsorption–desorption cycling while suppressing stable Co–Cl intermediates. Such asymmetric electronic modulation accelerates chlorine evolution kinetics and promotes a Ru‐dominant Volmer−Heyrovský pathway with reduced energy barriers. Benefiting from the optimized active‐site configuration, RuO _x ‐Co ₃ O ₄ with an ultralow Ru loading of only 1.64 wt.% delivers substantially higher CER activity than commercial dimensionally stable anodes (DSA), achieving a mass activity of 3049 A g _Ru ⁻¹ and a Cl ₂ selectivity of 98.9% at 1.5 V. This work highlights asymmetric site engineering as an effective strategy for developing highly efficient and selective CER electrocatalysts.