Effect of initial water content and calcination temperature on photocatalytic properties of TiO2 nanopowders synthesized by the sol–gel process

Abstract

The effects of initial water content and calcination temperature on sol–gel synthesized TiO2 powders were studied. Mother solutions had water/Ti-precursor mole ratios (R ratio) of 1, 5, 10, and 50. Dried aerogels were calcined for 3h at temperatures of 300, 400, and 500°C to obtain crystallized TiO2 nanopowders in the range of 15–30nm. FE-scanning electron microscopy and X-ray diffraction techniques were employed to investigate the morphological and structural properties of the nanopowders synthesized. Profound effect of gel viscosity was observed on the formation mechanism and extent of crystallinity in the powders. Methylene blue degradation test results suggest, photocatalytic performance is enhanced as initial water content and calcination temperature increased. Band-gap energy of the powders ranged from 3.09 to 3.27eV. Overall, this study shows that initial water content and calcination regime have a profound effect on the phase assembly, crystallite size, band-gap energy, and photocatalytic performance of sol–gel synthesized TiO2 nanopowders.