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

Abstract

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 Å and 9.87708 Å, 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 photocatalyst 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% BiSnSbO6/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. Eventually, working mechanism of BiMSbO6(M=Ti, Sn)/BiOBr heterojunction photocatalyst was described in detail.

Thickness Modification of BiOBr Nanosheets by Sn-TiO2 for Enhanced Photocatalytic Degradation of Antibiotics

“…The peaks at 458.6 and 464.4 eV corresponded to Ti 2p 3/2 and Ti 2p 1/2 energy levels, indicating the presence of Ti 4+ . The peaks at 486.5 and 494.8 eV corresponded to the Sn 3d 5/2 and Sn 3d 3/2 energy levels, indicating the presence of Sn 4+ . In addition, it was obvious that compared with the pure BiOBr sample the characteristic peaks of Bi 4f in the TSB-0.5 composite were all shifted toward the direction of low binding energy.…”

“…37 The peaks at 486.5 and 494.8 eV corresponded to the Sn 3d 5/2 and Sn 3d 3/2 energy levels, indicating the presence of Sn 4+ . 38 In addition, it was obvious that compared with the pure BiOBr sample the characteristic peaks of Bi 4f in the TSB-0.5 composite were all shifted toward the direction of low binding energy. Similarly, compared with pure T 60 S 1 samples, the characteristic peaks of Ti 2p and Sn 3d were also shifted toward the direction of low binding energy, which proved the formation of Sn-TiO 2 /BiOBr heterostructures.…”