Selective Catalytic Reduction of NO with NH₃ over Fe-ZSM-5 Catalysts Prepared by Sublimation of FeCl₃ at Different Temperatures

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• 作者：K. Krishna ; G.B.F. Seijger ; C.M. van den Bleek ; M. Makkee ; Guido Mul and H.P.A. Calis
• 关键词：sublimation ; FeCl3 ; Fe ; ZSM ; 5 ; selective catalytic reduction ; NO ; NH3 ; infrared spectroscopy
• 刊名：Catalysis Letters
• 出版时间：2003
• 出版年：2003
• 期刊代码：13_1011372X
• 类别：ch
• 卷：86
• 期：1/3
• 页码：121-132
• 数据来源：sp

摘要

Fe-ZSM-5 catalysts were prepared by subliming FeCl₃ into H-ZSM-5. The method used allowed Fe-ZSM-5 catalyst preparation by FeCl₃ exchange at a desired sublimation temperature and was found to be more precise. The sublimation of FeCl₃ into H-ZSM-5 was carried out at 320 and 700 °C. Fe-ZSM-5 prepared by sublimation of FeCl₃ at 320 °C followed by rapid heating to 700 °C and the catalyst prepared by subliming FeCl₃ at 700 °C were found to be more active for NO reduction with NH₃ in the presence of simulated exhaust gases containing water vapor than catalysts prepared by subliming FeCl₃ at 320 °C. To determine the active sites, the catalysts were characterized by H₂-TPR, in situ DRIFTS of NO adsorption, NH₃-TPD, XRD and chemical analysis methods. The observed NO conversion differences in selective catalytic reduction using NH₃ could be correlated to the iron cation species present at different locations determined from diffuse reflectance infrared spectroscopy. Enhanced NO reduction activity was obtained when positions in Fe-ZSM-5, corresponding to Fe2+(NO) band at 1877 cm-1 in DRIFTS, were preferentially occupied.