(517e) S Doped TiO2 synthesized By Novel One Step Liquid Flame Spray Pyrolysis (LFSP) for Photocatalytic Oxidation of CO in Visible Region

Inturi, S. N. R., University of Cincinnati
Boningari, T., University of Cincinnati
Suidan, M., American university of beirut
Smirniotis, P., University of Cincinnati
A novel single step Liquid Spray pyrolysis (LFSP) method is used to synthesize a series of S-TiO2 catalyst of nanosized crystals with dimensional homogeneity and high monodispersity. In order to improve the visible light response and to further narrow the band bap of TiO2 catalyst, Sulphur is used as the dopant in this method. With the change in the amount of S incorporated into TiO2 catalyst, we observed the generation of the successive energy bands inside the TiO2 band gap thus lowering the bandgap energy. The effects of nanosized S doped TiO2 catalyst on the visible light photocatalytic oxidation of gaseous CO were investigated. Our XPS results indicate that the nitrogen doping concentration could reach up to 8 wt% owing to the homogeneous doping in the mesoporous TiO2 catalysts. The nitrogen doped TiO2 catalyst exhibit such excellent characteristics as high specific area, relatively small particle size, pure anatase phase and excellent UV-vis absorption capacity in the range of 400-800 nm, which are all beneficial to the photocatalytic oxidation of CO under the visible light irradiation. The photo conversion of CO to CO2 is quantitative in the presence of O2. The photocatalytic CO oxidation rates and the amounts of N deposited on TiO2 surface show a close correlation. The addition of water vapor dose not affects significantly the CO photooxidation kinetics in the presence of O2. The main oxidants in CO Photocatalytic oxidation seem to be produced from adsorbed O2. The photocatalytic oxidation kinetics was investigated in detail as a function of S loading, coated TiO2 mass, CO concentration, O2 concentration, light intensity, additives, and humidity. These interesting results will be discussed in the presentation.