Preparation of TiO_2, Ag-doped TiO_2 nanoparticle and TiO_2-SBA-15 nanocomposites using simple aqueous solution-based chemical method and study of their photocatalytical activity

摘要

Nanocrystalline TiO_2, Ag-doped TiO_2 and TiO_2-SBA-15 nanocomposites have been synthesised using a simple aqueous solution-based chemical method. Nanocrystalline TiO_2 was synthesised by calcining the precursor prepared by using ethylenediamine tetraacetic acid and TiCl_3 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 TiO_2 was synthesised by doping of Ag during the synthesis step of TiO_2. TiO_2-SBA-15 nanocomposites were synthesised by impregnation method. Pure anatase TiO_2 nanoparticle was formed in the amorphous matrix of the silicate SBA-15, even though the loading of the TiO_2 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 TiO_2 exhibited enhanced photocatalytic activity than undoped TiO_2. TiO_2-SBA-15 nanocomposites showed impressive photocatalytic activity even with 10 wt% TiO_2 loading.