溴代甲烷在TiO2上的光催化降解研究

系统地研究了CH₃Br在溶胶-凝胶法制备的TiO₂催化剂上的气相光催化氧化行为,考察了催化剂煅烧温度、催化剂中残留NO-3、反应物料中的水份、反应温度等催化剂制备及反应条件对催化剂反应性能的影响,并结合XRD、BET比表面积和FTIR等表征结果对TiO₂催化剂的反应行为进行了解释.实验结果表明,CH₃Br在TiO₂上的气相光催化氧化是典型的一级反应,表观活化能为13.7kJ/mol.反应初始阶段存在显著的催化剂失活现象,催化剂高温煅烧,NO-3及水等对该反应活性都有明显的抑制作用,提高反应温度有利于改善催化剂的反应性能.

Photocatalytic Degradation of Bromomethane on Sol-gel Derived Titania

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 NO-3 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 BET method, FTIR spectroscopy 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 NO-3 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.