A facile and green strategy for large-scale synthesis of silica nanotubes using ZnO nanorods as templates

Hollow silica nanostructures exhibit important applications in catalysis, sensing, and gene delivery due to their increased surface areas, good biocompatibility, and unique optical features. Here we report a simple and green approach to synthesize silica nanotubes using environment-friendly ZnO nanorods as templates. The ZnO nanorods are first coated with a layer of uniform silica shell by a sol-gel method. Then silica nanotubes are derived from the ZnO@SiO2 nanohybrids after removal of the ZnO nanorod cores in diluted hydrochloric acid solution. The samples at different stages were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Energy-dispersive X-ray spectroscopy, and Transmission electron microscopy. By controlling the structure of the ZnO@SiO2 nanohybrids, such as shell thickness, and the diameter and length of ZnO nanorods, size controllable SiO2 nanotubes can be expected.