Fe3+-TiO2/SiO2气相光催化降解乙醛反应动力学研究

用浸渍法制备了Fe^3 -TiO2／SiO2负载型光催化剂，并进行了光催化降解气相中乙醛的实验和动力学研究．结果表明，Fe^3 掺杂量(nFe3 ／nTi4)为0．5％时光催化降解乙醛的效率最高；水气的存在提高了Fe^3 -TiO2／SiO2负载型催化剂的光催化活性，但使Fe^3 -TiO2纳米粉的光催化活性降低；O2的存在使Fe^3 -TiO2纳米粉和Fe^3 -TiO2／SiO2负载型催化剂的催化活性均有所降低；光强减弱使乙醛降解率下降，反应速率与光强之间呈近似线性关系；光催化降解气相中乙醛的动力学可以用Langrauir-Hinshelwood动力学方程描述．

Study on photocatalytic degradation and kinetics of acetaldehyde in gas phase using Fe3+ -TiO2/SiO2

Photocatalytic degradation of acetaldehyde using Fe~(3+)-TiO_2/SiO_2 thin film photocatalysts prepared by means of impregnation method has been performed in gas phase. The photocatalytic activity of prepared catalysts reach the maximum at the optimal content n_(Fe~(3+))/n_(Fe~(4+))=0.5%. The existence of water vapor makes the photocatalytic activity of Fe~(3+)-TiO_2/SiO_2 increase, but leads to an effective decline in the catalytic activity of TiO_2 nanoparticles. For both Fe~(3+)-TiO_2/SiO_2 thin film and TiO_2 nanoparticle catalysts, the presence of O_2 makes their photocatalytic activity decrease obviously. The degradation ratio of acetaldehyde declines along with the photo intensity weakening, and the relationship between photocatalytic reaction rate and light intensity can be approximately considered as linear. The experimental results also indicate that the kinetics of acetaldehyde degradation reaction can be described by Langmuir-Hinshelwood model. Furthermore, the kinetic equation model can slightly vary with initial acetaldehyde concentration, content of O_2 and water vapor, and light intensity.