Photocatalytic degradation of ibuprofen on S-doped BiOBr

Abstract

Doping heterogeneous atoms into BiOX is recognized as an effective method to improve its photocatalytic activity. Here, S-doped BiOBr (S-BiOBr) was synthesized via a solvothermal method in the absence of water, which is supposed to substitute O as S^2- in the lattice. This material is firstly used for the visible-light-driven degradation of ibuprofen, a model anti-inflammatory drug. The degradation efficiency of S-BiOBr is much higher than that of pure BiOBr. The degradation kinetic constant for S-BiOBr (2.48 × 10^-2 min^-1) is about 3 times as high as that of pure BiOBr (0.83 × 10^-2 min^-1). It is found that S-doping tunes the band structure of BiOBr, leading to a narrower band gap and thus higher utilization efficiency of visible light. The degradation of ibuprofen on S-BiOBr can be attributed to the generation of H₂O₂ and OH radicals. OH radical plays a synergistic role along with holes in the photocatalytic degradation process, which is supposed to be better than the reported single hole- or superoxide-dominant reaction. This work reveals a previously unrecognized and more efficient method for the degradation of organic contaminants on BiOBr.

Keywords: BiOBr; Doping; Ibuprofen; Oxygen vacancies; Photocatalytic degradation.