Tailoring the Mn–O Covalency and Surface Oxygen Defects of Ferrite Nanostructures for Peroxymonosulfate Activation and Norfloxacin Degradation

Activating peroxymonosulfate (PMS) by transition metal oxides has been widely applied to degrade organic pollutant. However, the synergistic effect of transition metal (TM)-O covalency and anion defects on PMS activation never been unveiled. In this work, a multiple spinel nanomicrosphere CoxMn1–xFe2O4 with oxygen vacancies (OVs) was synthesized to degrade antibiotics norfloxacin by activating PMS. Experimental and theoretical analysis showed that tunable Mn–O covalency by regulating the content of Co dopant was favorable to electron transfer, boosting PMS activation. Meanwhile, the introduction of OVs could further improve the activity of CoxMn1–xFe2O4. Consequently, CMF-OVs-0.5 with optimized Mn–O covalency and OVs contents exhibited the best catalytic activity. Moreover, the synergistic effect of Mn–O covalency and OVs was systematically investigated by being combined with various in/ex situ characterization. This work provides an insight on modulating the physicochemical property of TM oxides by cooperatively adjusting TM-O covalency and OVs to enhance PMS activation for degradation of norfloxacin.