Preparation of TiO2, Ag-doped TiO2 nanoparticle and TiO2-SBA-15 nanocomposites using simple aqueous solution-based chemical method and study of their photocatalytical activity

Nanocrystalline TiO2, Ag-doped TiO2 and TiO2-SBA-15 nanocomposites have been synthesised using a simple aqueous solution-based chemical method. Nanocrystalline TiO2 was synthesised by calcining the precursor prepared by using ethylenediamine tetraacetic acid and TiCl3 in aqueous medium. Formation of crystalline phase (anatase, rutile or mixed phase) and crystallite size were found to be dependent on calcination temperature. To enhance the photocatalytic activity, Ag-doped TiO2 was synthesised by doping of Ag during the synthesis step of TiO2. TiO2-SBA-15 nanocomposites were synthesised by impregnation method. Pure anatase TiO2 nanoparticle was formed in the amorphous matrix of the silicate SBA-15, even though the loading of the TiO2 in the silicate matrix was as low as 5 wt%. The synthesised materials were characterised using thermal analysis, powder X-ray diffraction method, surface area and porosimetry analysis, diffuse reflectance analysis and transmission electron microscopy. The photocatalytic property of the synthesised materials was investigated towards the degradation of methyl orange under sunlight exposure and monitored by UV-visible spectrophotometer. Ag-doped TiO2 exhibited enhanced photocatalytic activity than undoped TiO2. TiO2-SBA-15 nanocomposites showed impressive photocatalytic activity even with 10 wt% TiO2 loading.