Role of Temperature on the Phase Modification of TiO2 Nanoparticles Synthesized by the Precipitation Method

Nanostructured TiO2 samples have been synthesized successfully by a simple precipitation method. The prepared samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), photoluminescence (PL) spectroscopy, ultra violet (UV) spectroscopy and Raman spectroscopy respectively. The as-prepared TiO2 nanoparticls appear to be a single anatase phase with average crystalline size 37.68 nm at 150 degrees C and found to be transformed from anatase to rutile phase during the annealing of samples in the temperature range from 150 degrees C to 600 degrees C. The TEM images indicate the particle sizes are in the range between 12 and 25 nm for anatase phase TiO2 at 400 degrees C and 30-45 nm for rutile phase TiO2 at 600 degrees C. The luminescence property of the TiO2 nanoparticles studied by the emission properties confirms the presence of defect levels caused by the oxygen vacancies. Raman spectroscopy was used to identify and quantity the amorphous and crystalline TiO2 phases. FTIR studies reveal weak complex vibrations between the titanium and oxygen species and also additional unsaturated sites (Ti3+) through incorporation of (OH) groups, not otherwise seen in bulk TiO2.