Photocatalytic degradation of bromomethane on sol-gel derived titania

The photocatalytic degradation of bromomethane in airstreams was studied ov er the TiO2 catalysts prepared by sol-gel method. The influence of calcinat ion temperature, reaction temperature, the residual NO; in catalyst and wat er vapor on the structure of catalysts and their photocatalytic performance was examined by means of X-ray diffraction technique, Nz sorption analysis with BET method, FTIR spectroscopy and photocatalytic activity measurement . The results showed that the photocatalytic decomposition of CH3Br followe d first-order kinetics, and the apparent activation energy was determined t o be 13.7 kJ/mol. The distinct deactivation of TiO2 catalysts for the photo catalytic oxidation of bromomethane was observed in the initial period of r eaction. Some factors such as high calcination temperature, the residual NO B and water vapor in the feed stream decreased the photocatalytic activity of TiO2 catalysts. However, the reactivity of bromomethane is greatly enhan ced at increasing reaction temperatures. The effect of raising reaction tem perature has been ascribed to decreasing adsorption of water.