Construction of oxygen vacancy assisted Z-scheme BiO2-x/BiOBr heterojunction for LED light pollutants degradation and bacteria inactivation.

It is well known that the most important task of photocatalytic technology is to synthesize photocatalysts with compact heterojunction structure and high redox ability. To achieve the goal, a novel Z-scheme BiO2-x/BiOBr heterojunction containing oxygen vacancy was synthesized by an in-situ generation process. Several techniques, X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) have verified the BiO2-x/BiOBr heterojunction. XPS and electron spin resonance (ESR) reveals the presence of oxygen vacancy in the BiO2-x/BiOBr composite. As expected, the BiO2-x/BiOBr composite showed good performance in removing Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Rhodamine B (RhB) and tetracycline (TC). The effects of inorganic ions, pH value and water matrix were investigated with many details. The active species and proposed mechanism were revealed by trapping experiment and related characterizations. The synergistic effect of oxygen vacancy and Z-scheme heterojunction makes the BiO2-x/BiOBr composite possess excellent photocatalytic activity.