Effect of hydrothermal synthesis on the particulate characteristics of Nanocrystalline titanium dioxide

Nanocrystalline Titanium dioxide particles have been synthesized through hydrothermal method to study the effect of autoclaving temperature and annealing temperature on their particulate characteristics. The nanoparticles have been synthesized using a Titanium alkoxide precursor at two different temperatures 160 degrees C and 200 degrees C for 14h and annealed at 450 degrees C. X-ray diffraction studies were used to ascertain the tetragonal structure and the anatase phase represented by the synthesized samples. The particle size of the synthesized material was derived using the Scherrer formula and it was found to be of the order of 10 - 20 nm. The optical absorption spectrum reveals the absorption-edge to be slightly red-shifted. The band gap of the synthesized materials was evaluated using the Tauc plot and it was determined to be similar to 3.25 +/- 0.02eV. The emission spectrum for the sample was recorded at an excitation wavelength of 295 nm and the flat bands were found to depict the inherent defect states. Although the FE-SEM images display a high agglomeration, they reveal the morphology of the particulates to be a spherical one. The HR-TEM images of the sample clearly corroborate with the spherical morphology and the particle size as represented by FESEM and XRD studies respectively. (C) 2015Elsevier Ltd. All rights reserved.