Effect of modified iodine on defect structure and antibacterial properties of ZnO in visible light

Iodine-modified ZnO with oxygen vacancies were synthesized by the solvothermal method. The crystal structure, morphology, optical properties and defects of as-prepared samples were characterized by XRD, SEM, DRS, XPS and ESR. The photocatalytic disinfection activity of I-modified ZnO in the dark and under visible light irradiation were investigated by the antibacterial drop-test method. The results showed that the iodine mainly exists in the form of I- in the ZnO. The modified iodine increases the numbers of oxygen vacancies of ZnO as the amount of iodine increases. In addition, the I-ZnO exhibits much higher antibacterial activity than that of pure ZnO and was stable during the photocatalytic process. The enhanced antibacterial activity of I-ZnO is attributed to the co-operation of the oxygen vacancies and the iodine which promotes the separation of photo-generated carriers and subsequently produces more ROS (reactive oxygen species).