3D hierarchical H2-reduced Mn-doped CeO2 microflowers assembled from nanotubes as a high-performance Fenton-like photocatalyst for tetracycline antibiotics degradation

Developing of active and synergistic system is fundamentally important to rapidly and efficiently remove persistent toxic and hazardous pollutants. Herein, we report a coupling system by integrating sulfate radical-based Fenton-like process with visible light-driven photocatalysis for fast removal of three typical tetracycline antibiotics in water, i.e., tetracycline (TC), chlortetracycline (CTC), and oxytetracycline (OTC), where the newly-designed nanotubes-assembled 3D hierarchical H2-reduced Mn-doped CeO2 microflowers (re-Mn-CeO2 NMs) are developed as efficient Fenton-like photocatalyst for peroxymonosulfate (PMS) activation. The obtained re-Mn-CeO2 NMs samples, featuring large surface area, good visible light response, excellent redox properties, and abundant oxygen vacancy, exhibit appreciable adsorption capacity, remarkable catalytic performance, and favorable stability. Especially, in the optimal reaction system (re-7Mn-CeO2 NMs/PMS/Vis), the degradation efficiencies of TC, CTC, and OTC reach up to 98.6%, 97.4%, and 88.1% only in 10 min of irradiation. All residues can be completely eliminated in 60 min, which is ∼1.1 and 2.0-fold higher than those of Fenton-like reaction and photocatalysis alone, confirming the synergistic effect of Fenton-like process and photocatalysis occurred in the coupling system. Moreover, the possible decomposition pathways, main reactive oxygen species, and reasonable enhanced mechanism for the Fenton-like photocatalytic system are systematically investigated. Our findings highlight that the Fenton-photocatalysis synergy holds great promising for environment remediation, and offer a feasible means to tune the performance of CeO2-based materials especially in Fenton-like photocatalytic oxidation of antibiotics.