Magnetic heterojunction of oxygen-deficient Ti3--TiO2 and Ar-Fe2O3 derived from metal-organic frameworks for efficient peroxydisulfate (PDS) photo-activation

The light collection and separation of nano-catalysts in the slurry-system are key issues in photocatalysis. Herein, magnetic Ti3+-TiO2/Ar-Fe2O3 type II heterojunction is fabricated by high-temperature reduction of MOFs in argon atmosphere for solving these issues. The Fe clusters exposed by Ar-Fe2O3 and the high light collection ability brought by oxygen vacancies make Ti3+-TiO2/Ar-Fe2O3 considered for photo-activation of peroxydisulfate (PDS). Ti3+-TiO2/Ar-Fe2O3/visible light/PDS system degrades 97.80 % of Norfloxacin (NOR) within 5 min, the first-order kinetic constants (0.4174 min(-1)) is 8.73 and 7.31 times that of Ti3+-TiO2 and Ar-Fe2O3. The proposed system also exhibits excellent degradation ability in multiple antibiotics and real samples. Based on the suitable energy band level of Ti3+-TiO2/Ar-Fe2O3, the separation rate of carriers is enhanced, SO4 center dot-, center dot OH and h(+) are concomitantly produced for oxidating NOR. This work enriches in-situ defect engineering for TiO2, gives novel insights for MOFs-assisted nano-catalysts and offers a new chance for photo-activation of PDS.

Automated summary

This study successfully addressed the issues of light collection and separation of nano-catalysts in the slurry-system by fabricating a magnetic Ti3+-TiO2/Ar-Fe2O3 type II heterojunction. The proposed system showed excellent degradation ability in multiple antibiotics and real samples, offering a new chance for the photo-activation of peroxydisulfate (PDS). The high light collection ability and exposed Fe clusters in Ar-Fe2O3, coupled with suitable energy band levels of Ti3+-TiO2/Ar-Fe2O3, enhanced carrier separation rates and led to the production of active species for oxidizing NOR.