Electron-flow-driven redox cycling in CN-supported CoFe2O4 enables intensified peroxymonosulfate activation for tetracycline degradation

A CN-supported CoFe 2 O 4 catalyst was rationally developed to intensify peroxymonosulfate (PMS) activation for tetracycline degradation through interfacial electronic regulation. Beyond conventional structure-centered strategies, this study identifies directional electron donation from CN to CoFe 2 O 4 as the fundamental origin of catalytic enhancement, which accelerates the Co (III)/Co (II) and Fe (III)/Fe (II) redox cycles and thereby sustains PMS activation. Consequently, the composite delivers markedly superior catalytic reactivity, pronounced tolerance to ionic perturbation, and robust performance in complex aqueous matrices. Quenching and EPR analyses collectively reveal a nonradical-dominated oxidation regime, in which 1 O 2 serves as the principal reactive species, accompanied by minor contributions from O 2 • - , SO 4 • - , and •OH. XPS further corroborates the dynamic valence evolution of Co and Fe, validating an electron-transfer-assisted redox cycling mechanism. LC-MS and toxicity assessment demonstrate stepwise tetracycline transformation with an overall attenuation of mutagenic risk. These findings establish interfacial electron flow as a governing descriptor for PMS activation and provide a mechanistic framework for catalyst design at the electronic-structure level.