Non-Aqueous Preparation of High-Crystallinity Hierarchical TiO2 Hollow Spheres with Excellent Photocatalytic Efficiency

High-crystallinity hierarchical anatase TiO2 hollow spheres were prepared by a high-temperature (350 degrees C) and nonaqueous solvothermal method in the absence of water, templates, or additives. The hollow structures were assembled from highly crystallized TiO2 nanoparticles and exhibit superior photocatalytic properties relative to those of Degussa P25 TiO2 under irradiation with UV light. The influence of reaction temperature on the crystallinity, morphology, crystallite shape and size, band gap, specific surface area, and pore size distribution of TiO2 has been studied in detail. It is evident that reaction temperature is the most important factor to increase the crystallinity of TiO2 in order to improve its charge transfer and transport properties, which are important in photocatalysis.