Abstract: The photocatalytic degradation of bromomethane in airstreams was studied over the TiO₂ catalysts prepared by sol-gel method. The influence of calcination temperature, reaction temperature, the residual NO₃^- in catalyst and water vapor on the structure of catalysts and their photocatalytic performance was examined by means of X-ray diffraction technique, N₂ sorption analysis with BETmethod, FTIRspectroscopy and photocatalytic activity measurement. The results showed that the photocatalytic decomposition of CH₃Br followed first-order kinetics, and the apparent activation energy was determined to be 13.7 kJ/mol. The distinct deactivation of TiO₂ catalysts for the photocatalytic oxidation of bromomethane was observed in the initial period of reaction. Some factors such as high calcination temperature, the residual NO₃^- and water vapor in the feed stream decreased the photocatalytic activity of TiO₂ catalysts. However, the reactivity of bromomethane is greatly enhanced at increasing reaction temperatures. The effect of raising reaction temperature has been ascribed to decreasing adsorption of water.

Key words: Bromomethane, Titania, Photocatalysis