Fabrication oxygen defect-mediated double Z-scheme BiOI/BiO2-x/BiOBr photocatalyst for pollutions degradation and bacteria inactivation

Abstract In view of the influence of various pollutants and harmful bacteria in the environment, we designed and constructed BiOI/BiO2-x/BiOBr successfully, a double transfer Z-scheme photocatalyst containing oxygen defects. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM) and Scanning electron microscope (SEM) show that the double transfer Z-scheme composite is successfully prepared. XPS and ESR techniques verify the oxygen defects in the composite photocatalyst. Photocurrent and Electrochemical impedance spectroscopy (EIS) measurements show the high separation efficiency of photogenerated carriers in the composite photocatalyst. It is found that the best proportion of 35% IOB composite can degrade two pollutants and inactivate two harmful bacteria: 99.6% Rhodamine B (RhB) can be removed within 60 min; 81% tetracycline (TC) could be degraded in 90 min; 100% Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) can be destroyed in 15 min. We also explored the influences of pollutant concentration, photocatalyst dosage, pH value, anion of inorganic compounds and water substrate on pollutant removal. In addition, the photocatalytic degradation under LED light broadens the practical application of photocatalyst. This work not only provides a new idea for the preparation of photocatalysts with high redox ability, but also broadens its application in environment wastewater treatment.