Controlled synthesis and characterization of TiO ₂ nanoparticles via a sol-gel method

The properties influencing the photocatalytic activity of TiO ₂ particles have been suggested to include the surface area, crystallinity, crystallite size and crystal structure. Therefore, manipulation of the microstructure of titania, especially of nanocrystalline powders, is very important in the preparative process. In this study, nanocrystalline TiO ₂ powders with controlled particle size and phase composition were synthesized at low temperature (<80°C) by a modified sol-gel method. The effects of gelation temperature were systematically investigated. It was found that this parameter played a critical role in determining the crystallinity of single phase anatase. With increasing gelation temperature, the crystallinity of anatase improved initially and then decreased if the temperature was raised to 80°C. These nanomaterials were characterized comprehensively by powder X-ray diffraction (including Rietveld analysis), high-resolution transmission electron microscopy, DSC/TGA thermal analysis and UV-Vis spectrometry.