Synthesis of caged Iodine-modified ZnO nanomaterials and study on their visible light photocatalytic antibacterial properties

•A nano-scale Iodine-modified ZnO(I-ZnO-n) material rich in oxygen defects has been prepared via reflux method.•The presence of Iodine, and the cage structure of I-ZnO-n are benefit to reduce the recombination of photogenic electron-hole pairs.•The oxygen vacancy is beneficial to the separation of photo-excited charge carriers and generate much more free radicals.•The antibacterial performance of I-ZnO-n has greatly improved compared with the Iodine-modified ZnO micron materials (I-ZnO-m) and ZnO.