Preparation Of TiO₂/Sr₂CeO₄ And Gas-phase Photocatalytic Oxidation Of Benzene

The third period of pollution is coming which is characterized by the indoor air contaminants as the main source. There are more than one hundred kinds of contaminants in the indoor air, which badly menaced the health of man. Benzene is a typically harmful pollutant. Due to the stable structure of benzene, it is difficult to degrade by the common techniques. Gas-phase photocatalytic oxidation of benzene is a promising and effective method. But pure TiO₂ has low activity and deactives easily. In order to solve this problem, researchers all over the world have studied the loaded catalysts. In this study, we chose fluorescent material as the support of TiO₂ and prepared the loaded photocatalyst. With initial concentration of 1.0mg/l benzene as simulated gas, the photocatalytic ability of the catalyst and the kinetic parameter of benzene degradation were investigated, the affect by doping Fe³⁺ into TiO₂ and adding H₂O was studied, and a series of meaning results were obtained.The results show that choosing the fluorescent material as the support can effectively improve the performance of photocatalyst. The benzene conversion is the best when TiO₂ loading is 1.0wt%, which is 1.01 times more than that of pure TiO₂, the lifetime of catalyst is 2.00 times as long as that of pure TiO₂.The benzene conversion is promoted by doping Fe³⁺ into TiO₂ or adding H₂O into the reactor. The kinetic parameter of benzene degradation in gas phase before deactivity of photocatalyst was also studied. The degradation of benzene is first-order reaction.The results of XRD measurement indicate that TiO₂ is anatase after being calcined at 450 ℃. The results of UV-VIS. reflectance show the loaded catalyst hasmore absorption in visible region than pure TiO2. The XPS results show the binding energy of TiCV Sr2CeO4 increases l.Oev compared with pure T1O2, which indicates that there is the strong interaction between TiO2 and S^CeOzt, and results in higher activity than pure TiC>2.The IR spectrum shows the appearance of phenyl and hydroxyl on the surface of catalyst, combined with the results of GC-MS, we can concluded that the accumulation and occupation of active site by these intermediates lead to the deactivity of the catalyst. The photocatalytic oxidation mechanism of benzene is proposed under this condition.