N2O decomposition over wet- and solid-exchanged Fe-ZSM-5 catalysts
N2O decomposition over wet- and solid-exchanged Fe-ZSM-5 catalysts
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DOI：
10.1016/j.apcatb.2007.09.020
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发表时间：
2008-02
影响因子：
22.1
通讯作者：
Joo-hyoung Park;Jong-Hyun Choung;I. Nam;S. Ham
中科院分区：
文献类型：
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作者：
Joo-hyoung Park;Jong-Hyun Choung;I. Nam;S. Ham
Fe-ZSM-5的N2O分解活性很大程度上取决于铁含量和制备方法，包括湿态（WIE）和固态离子交换（SSIE）。本文系统地考察了一系列不同铁含量的Fe- zsm -5催化剂的制备方法及其对N2O分解活性的影响。Fe- zsm -5- ssie的分解活性总体趋势高于Fe- zsm -5- wie，说明在离子交换过程中，Fe在催化剂表面形成了独特的局部结构。基于Fe- zsm -5- ssie和-WIE系列催化剂的傅立叶变换Fe K-edge EXAFS谱，高铁负载的Fe- zsm -5- ssie表面的大部分铁以氧桥双核形式分散。假设Fe/Al=0.20和Fe/Al=0.65的Fe- zsm -5- ssie样品表面仅含有单核和双核Fe作为活性反应物质，在干湿条件下N2O分解的周转率（TOF）得到了证实。Fe- zsm -5- ssie的高性能可能主要是由于在催化剂制备过程中在其表面形成了双核铁。
The N2O decomposition activity of Fe-ZSM-5 strongly depends on the iron content and the preparation methods, including wet (WIE) and solid state ion exchanges (SSIE). The state of Fe species formed on the surface of a series of Fe-ZSM-5 catalysts containing a variety of Fe contents with respect to the preparation method and their role for N2O decomposition activity have been systematically examined. The general trend for the decomposition activity of Fe-ZSM-5-SSIE is higher than that of Fe-ZSM-5-WIE, indicating the formation of a distinctive local structure of Fe on the catalyst surface during the course of the ion-exchange procedure. Based upon the Fourier transformed Fe K-edge EXAFS spectra for the series of Fe-ZSM-5-SSIE and -WIE catalysts, most of the Fe species on the surface of Fe-ZSM-5-SSIE with high Fe loading are well dispersed in the form of oxygen-bridged binuclear Fe species. The turnover frequency (TOF) for N2O decomposition under dry and wet conditions has been confirmed assuming that Fe-ZSM-5-SSIE samples with Fe/Al=0.20 and Fe/Al=0.65 only contain mononuclear and binuclear Fe species, respectively, as active reaction species on their surface. The high performance of Fe-ZSM-5-SSIE may be mainly due to the formation of the binuclear Fe species onto its surface during the preparation of the catalyst.