Oxygen vacancies-enriched CoFe₂O₄ for peroxymonosulfate activation: The reactivity between radical-nonradical...

Oxygen vacancies (O_V) play a vital role in catalytic activity. Herein, a series of MOF-derived CoFe₂O₄ nanomaterials with O_V tuned by a simple thermal aging strategy are prepared for peroxymonosulfate (PMS) activation. Remarkably, the stability, structural and catalytic properties show dependence on the annealing temperature. The abundant surface O_V and functional groups on CoFe₂O₄ were verified as active sites to boost catalytic activity. Based on the density functional theory (DFT) calculations, (1 1 1), (2 2 2) and (4 2 2) planes exposed at higher temperatures facilitate catalytic performance, ascribed to the intense surface adsorption energy. The quenching and electron paramagnetic resonance (EPR) experiments indicate catalysis degradation is a radical-nonradical coupling process. The reactivity between reactive oxygen species (ROS) and bisphenol A and the radical-nonradical dual degradation pathways are systematically explored by combined DFT and HPLC-MS.