Conventional peroxymonosulfate (PMS) activation often depends on nonselective radicals, limiting efficiency and selectivity. Precise nonradical pathways based on singlet oxygen (1O2) or high-valent metal oxo species under mild conditions remain difficult to realize. A single-atom cobalt-organic framework (Co SA-MOF) integrates hydrogen bonding and pollutant-mediated dual electron transfer, enabling highly efficient and selective nonradical PMS activation. Mixed cobalt valence states and N–H ligands establish an internal pathway in which isolated Co(II)/Co(III) sites with N–H ligands act as a redox engine. Density functional theory (DFT) shows that N–H groups lower the energy barriers for Co(IV)–O formation and Co(IV)–O conversion to 1O2, rationalizing the observed nonradical selectivity. Pollutants such as sulfadiazine serve as external electron donors in electrochemical tests, regenerating Co(III) and accelerating the Co(II)/Co(III) cycle. Molecular dynamics simulations indicate that confined pores provide PMS near bulk water diffusivity and promote pore enrichment and activation. This dual drive mechanism yields nearly complete sulfadiazine removal within 1 min, with nonradical pathways accounting for 80%, PMS utilization above 95%, and high catalytic stability. In a 10 L continuous-flow reactor, cobalt leaching remains below 2.63 μg/L, and a life cycle assessment (LCA) indicates a smaller environmental footprint than a Co3O4/PMS system does, providing design guidance for environmentally relevant nonradical PMS catalysts.
Zhou et al. (2026) studied this question.