Engineering a Co-O-V tripod electron bridge to promote non-radical PMS activation via high-valent Co(IV)=O

Single-atom catalysts have shown promise to generate high-valent metal-oxo species for PMS-based advanced oxidation processes (AOPs). Herein, we report a heteroatom-free crystalline V₃O₇·H₂O-supported single-atom Co catalyst (Co-VOH) for the efficient degradation of sulfamethoxazole (SMX). The Co-VOH/PMS system achieved rapid removal of 10 mg L^-1 SMX within 15 min, with a modified apparent second-order rate constant as high as 1228 min^-1 M^-1, outperforming most reported Co-based catalysts. This is primarily attributed to the dominant nonradical pathway driven by selective generation of Co(IV)=O. The catalyst forms a Co-O-V tripodal electron bridge, where under-coordinated V atoms withdraw electrons from Co sites, enabling efficient electron transfer and modulation, as elucidated by extensive spectroscopic and theoretical analyses. This unique structure enhances PMS adsorption and activation by promoting the cleavage of O-H and O-O bonds. Furthermore, the Co-VOH/PMS system demonstrated broad-spectrum degradation capability toward various emerging contaminants and remarkable stability in the presence of common inorganic ions, in real water samples, and under continuous-flow conditions in a microreactor, highlighting its strong environmental adaptability and application potential. This study introduces an atomically engineered, heteroatom-free catalyst with tailored electronic properties for PMS activation, providing new insights into the development of selective nonradical AOP systems for water decontamination.