Improved photocatalysts for gas phase detoxification.

摘要

Tungsten-titania and tungsten-SiO2-TiO2 metal oxides were synthesized using the impregnation method. In addition, a titanium dioxide catalyst was prepared using USY zeolite as support by the precipitation method. Finally, a titania-silica catalyst was prepared using the sol-gel technique. The commercial catalysts TiO2 P25, 8% SiO2-TiO 2, Al2O3-TiO2, and Fe2O 3-TiO2 were also investigated.;Characterization of the photocatalysts was achieved using x-ray diffraction (XRD), transmission electron microscopy (TEM), and total surface area measurements. In addition, the photocatalytic properties of the materials were studied by activity measurements using the oxidation of toluene in air.;The silica-titania catalyst prepared by sol-gel showed the highest photoactivity and the slowest deactivation rate.;Tungsten-containing catalysts were active under visible light, but less active than under ultraviolet illumination.;The greater adsorption capacity of the TiO2/USY catalyst did not result in a more active material.;A suitable model involving adsorption for the kinetics of toluene oxidation over WO3/SiO2-TiO2 (IW,1:2,830) could not be obtained. A power rate law model revealed that the reaction order with respect to toluene was close to zero. (Abstract shortened by UMI.)