Boosting singlet oxygen generation through peroxymonosulfate activation over CeO2-supported CuO catalyst to enhance degradation of fluorinated antibiotic.

Herein, a novel CeO2-supported CuO composite (denoted as CuO/CeO2) is rationally designed and synthesized via a facile strategy for peroxymonosulfate (PMS) activation to degrade fluorinated antibiotic (namely florfenicol). Benefiting from the synergistic effects between CeO2 and CuO, abundant Ce3+/Ce4+ and Cu+/Cu2+ redox couples and oxygen vacancies are formed in the composite, which can significantly accelerate interfacial charge transfer and provide sufficient active sites. The optimized CuO/CeO2 catalyst shows exceptional catalytic performance, achieving 95.9% removal efficiency of florfenicol within 16 min, together with excellent pH adaptability, anti-interference capacity, and reusability. The mechanistic analysis reveals that PMS is firstly adsorbed on the CuO/CeO2 surface to form CuO/CeO2-PMS* complexes, which then undergoes disproportionation to produce 1O2. Meanwhile, O2•- can also transform PMS into SO5•‒, which further decomposes into 1O2. The nonradical pathway dominated by 1O2 is responsible for the degradation of florfenicol, whereas radical species and high-valent copper contribute minimally. All in all, this work provides a high-efficiency strategy for selective 1O2 generation in advanced oxidation processes, offering a promising approach for fluorinated antibiotic wastewater remediation.