Gd/TiO_2气相光催化降解乙烯的动力学研究  

Study on Photocatalytic Degradation and Kinetics of Ethylene in Gas Phase over Gd^(3+)-doped TiO_2

作　　者：黄雅丽[1] 李旦振[2] 付贤智[2] 王绪绪[2] 

机构地区：[1]闽江学院化学与化学工程系,福建福州350108 [2]福州大学光催化研究所,福建福州350002

出　　处：《稀土》2007年第6期43-48,52,共7页Chinese Rare Earths

基　　金：闽江学院科研育苗项目(YKY06002)

摘　　要：采用溶胶-凝胶法和浸渍法制备了Gd3+掺杂TiO2光催化剂Gd/TiO2,以乙烯作为模拟污染物进行气相光催化降解实验,研究乙烯的流速、催化剂的粒径、热效应、反应温度等动力学因素对光催化降解反应的影响。结果表明,乙烯的流速≥20mL.min-1时,光催化活性趋于稳定;粒径大小对光催化活性基本上没有影响。乙烯在纯TiO2和Gd/TiO2样品上的光催化氧化是一级反应,光催化活性随着反应温度的升高而增强,其中,Gd/TiO2样品的光催化性能随反应温度的变化更显著。纯TiO2和Gd/TiO2样品的表观活化能分别为21.5 kJ.mol-1和16.3 kJ.mol-1,反应活化能降低,反应速率加快可能是纯TiO2掺杂Gd3+后光催化活性提高的动力学方面的原因。The Gd^3＋ - doped TiO2 photocatalyst was prepared by means of sol--gel and impregnation method. The activities of TiO2 and Gd^3＋ - doped TiO2 catalysts for photocatalytic degradation of ethylene had been performed in gas phase. The kinetic effects of the flow rate of ethylene, particulate radius, thermal effect and reaction temperature on the photocatalytic degradation of ethylene were examined,respectively. The results showed that the photocatalytic activities went steady when the flow rate of ethylene was no less than 20 mL · min^-1. Furthermore, the particulate radius hardly had effect on the activities. The experimental results also indicated that the photocatalitic degradation reactions of ethylene over TiO2 and Gd /TiO2 were followed by first order kinetics. Their degradation ratio enhanced along with the reaction temperature increasing and the activities of Gd /TiO2 increased more significantly. The apparent activation energy of TiO2 and Gd/TiO2 was 21.5kJ · mol^-1 and 16.3kJ · mol^-1. Therefore, the larger photocatalytic activity of Gd/TiO2 may be attributed to the lower activation energy and higher reaction rate.

关 键 词：气相光催化 Gd^3+掺杂 乙烯 反应动力学 

分 类 号：O643.3[理学—物理化学] O614.33[理学—化学]