Encapsulated Nanoconfined Microenvironment and Fluorine Coordination Boost Selective Peroxymonosulfate Activation Toward Co(IV)=O Dominated High‐Efficiency Pollutant Degradation and Biotoxicity Abatement

ABSTRACT High‐valent cobalt‐oxo (Co(IV) = O) is a type of powerful non‐radical reactive substance in the peroxymonosulfate (PMS)‐based advanced oxidation processes (AOPs). Nevertheless, its formation is challenging arising from the high 3d‐orbital occupancy of Co impeding binding with a terminal oxygen ligand. This study innovatively proposed a unique spherical core‐cavity‐shell catalyst comprising nitrogen‐doped carbon‐encapsulated CoF 2 nanoparticles (denoted as x ‐CoF 2 @NC) for efficient PMS activation toward selective generation of Co(IV) = O. The boosted Co(IV) = O generation was attributed to the strong electronegativity of fluorine, which significantly enhanced the surface charge polarization and reduced the local electron density at cobalt active sites. Moreover, the encapsulated nanoconfined microenvironment facilitated the enrichment of reactants within the catalyst's internal cavities, prolonging their residence time and improving the utilization efficiency of Co(IV) = O. As a result, the Co(IV) = O dominated 3‐CoF 2 @NC/PMS system exhibited outstanding catalytic activity and remarkable environmental robustness. Within 5 min, it can achieve a 100% removal of sulfamethazine (SMT) with low Co leaching. Moreover, it showed good performance in diverse water matrices and can be extended for dealing with multiple organic contaminants. Additionally, SMT pollutant degradation pathways are elucidated and the biotoxicity abatement is verified. This study lays a foundation for the future development of efficient environmental catalysts capable of selectively generating Co(IV) = O for organic wastewater treatment.