Comparison of alkaline pre-treatment of MFI zeolites for N₂O decomposition: different zeolite sources

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• 作者：Minfang Wu ; Xinqing Chen ; Liangshu Zhong ; Hui Wang ; Xinyan Zhang ; Qun Shen ; Wei Wei and Yuhan Sun
• 刊名：Greenhouse Gases: Science and Technology
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：6
• 期：5
• 页码：710-723
• 全文大小：1946K
• ISSN：2152-3878

文摘

Three MFI parent zeolites with different morphological properties by different synthesis method were adopted. Alkaline treatment using sodium hydroxide was introduced to modify the structure of MFI zeolites. After iron exchange, the catalytic performance of both parent and modified MFI zeolites were evaluated in the N₂O decomposition. The physicochemical properties were systematically characterized with various technologies, such as N₂ adsorption-desorption, ICP, XRD, UV-Vis, ²⁷Al MAS-NMR, TEM. The experiment results prove that the Fe-modified MFI catalysts with alkaline pre-treatment show much better catalytic activity than Fe-exchanged parent MFI catalysts. The curves of catalytic activities could move to low temperature range by 50‒100 °C. Furthermore, in the presence of NO, the performance gap between Fe-Seed-M, Fe-Solid-M, and Fe-Com-M three samples is obviously reduced. Amongst, for the Fe-Solid-M sample synthesized by the solvent-free method, 90% N₂O conversion could be attained at 500 °C, which shows potential to be applied the real condition. It is believed the hierarchical properties and the removal of amorphous substance is beneficial to the diffusion of ion exchange process. Therefore, the increase of active iron sites contributes to the improvement of catalytic performance.