Enhanced photocatalytic activation of peroxymonosulfate over oxygen vacancy-engineered Fe-doped CeO2

A visible-light-assisted peroxymonosulfate (PMS) activation system based on Fe-doped CeO 2 was developed for the efficient degradation of ofloxacin (OFX) in aqueous environments. Fe incorporation effectively regulated the electronic structure of CeO 2 , leading to enhanced visible-light utilization, promoted charge separation, and accelerated interfacial electron transfer, thereby facilitating PMS activation. The optimized 10% Fe-CeO 2 catalyst exhibited remarkably enhanced catalytic activity, achieving nearly complete OFX degradation within 10 min with an apparent rate constant of 0.3606 min −1 , which was substantially higher than that of pristine CeO 2 and the corresponding control systems. Comprehensive characterizations revealed that Fe incorporation optimized the local electronic environment of CeO 2 , thereby facilitating charge migration and PMS activation. Reactive species quenching experiments combined with electron paramagnetic resonance analyses confirmed that multiple reactive oxygen species, including superoxide radicals (O 2 •- ), sulfate radical (SO 4 •- ), hydroxyl radical ( • OH), and singlet oxygen ( 1 O 2 ), participated synergistically in the degradation process. Density functional theory calculations further revealed that Fe incorporation optimized the electronic distribution of CeO 2 and strengthened the adsorption and electron transfer of PMS and O 2 on the catalyst surface, thereby promoting the generation of oxidative species. This work provides mechanistic insight into Fe-mediated electronic structure modulation for efficient PMS activation and offers a feasible strategy for the rational design of ceria-based photocatalysts for environmental remediation.