Visible-Light-Driven p-n Type BiMSbO6(M=Ti, Sn)/BiOBr Heterojunction Photocatalyst toward Degradation of Levofloxacin

摘要

A new visible light-driven p-n type BiMSbO6(M=Ti, Sn)/BiOBr heterojunction photocatalyst was prepared in this paper. The XRD results showed that pure BiTiSbO6 and pure BiSnSbO6 crystallized well with the pyrochlore-type structure, stable cubic crystal system by space group Fd3 m and the XPS results further confirmed its high crystallinity. The crystal parameters of pure BiSnSbO6 and pure BiTiSbO6 were 10.23459 A and 9.87708 A, respectively. After visible light irradiation for 100 minutes, the removal rate of levofloxacin with 5 wt%, 10 wt% or 20 wt% BiMSbO6(M=Ti, Sn)/BiOBr heterojunction photo- catalyst could all reach more than 85%, which was far higher than that with pure BiSnSbO6 (4.79%) as a photocatalyst or that with pure BiTiSbO6 (5.35%) as a photocatalyst. In addition, the form of p-n heterojunction improved the reusability of pure BiOBr. After four cycles of photodegradation experiments for levofloxacin, the removal rate of levofloxacin with 20 wt% BiTiSbO6/BiOBr heterojunction photocatalyst or 10 wt% BiSnS- bO6/BiOBr heterojunction photocatalyst decreased by 11.48% or 11.02%. However, the removal rate of levofloxacin with pure BiOBr decreased by 18.68%. Moreover, h+ contributed the most during the degradation procedure of levofloxacin with BiMSbO6(M=Ti, Sn)/BiOBr heterojunction photocatalyst. Even- tually, working mechanism of BiMSbO6(M=Ti, Sn)/BiOBr hetero- junction photocatalyst was described in detail.