Preparation, characterization and antibacterial activity of core-shell Cu2O@Ag composites

Monodisperse Cu2O colloidal spheres were produced by a sol-gel reaction. The Cu2O@Ag composite spheres with core-shell structure were prepared by photodeposition route. The size and shape as well as the optical properties of the composites were characterized with transmission electron microscopy (TEM) and UV-vis spectroscopy. The results showed that the average particle size of Cu2O among the composites was about 150 nm, and the average particle size of Ag nanoparticles (NPs) was around 8 nm. Ag NPs were relatively monodisperse and presented spherical shape, and their deposition on the Cu2O surface was uniform. Formation of metallic Ag NPs on the surface of Cu2O spheres was also confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The antibacterial activity of the as-synthesized Cu2O spheres and Cu2O@Ag composites was also investigated. Owing to the synergistic action between Cu2O and Ag NPs, the Cu2O@Ag composites exhibit more excellent antibacterial activity compared to the pristine Cu2O.