A simple one-step fabrication of micrometer-scale hierarchical TiO2 hollow spheres

Hierarchical TiO2 hollow spheres had been prepared based on bubble templates by a simple one-step hydrothermal method. The diameter of hollow spheres was about 700 nm and the shell thickness of them was 69 nm. They were composed of similar spindle- or needle-like building units. Furthermore, hydrothermal time had an important influence on the morphology and crystallinity of hollow spheres. Moreover, the UV–Vis diffuse reflectance spectra of TiO2 hollow spheres heated at 150 °C for 10 h showed the strongest absorption in the UV–Vis region and the Raman spectrum demonstrated the anatase sample. Additionally, a possible formation mechanism of TiO2 hollow spheres was proposed. So this novel and simple method would provide a development direction to fabricate all kinds of inorganic hollow spheres by one-step procedure.