Economical Way to Synthesize SSZ-13 with Abundant Ion-Exchanged Cu+ for an Extraordinary Performance in Selective Catalytic Reduction (SCR) of NOx by Ammonia

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• 作者：Biaohua Chen ; Ruinian Xu ; Runduo Zhang ; Ning Liu
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：December 2, 2014
• 年：2014
• 卷：48
• 期：23
• 页码：13909-13916
• 全文大小：379K
• ISSN：1520-5851

文摘

In this study, an economical way for SSZ-13 preparation with the essentially cheap choline chloride as template has been attempted. The as-synthesized SSZ-13 zeolite after ion exchange by copper nitrate solution exhibited a superior SCR performance (over 95% NO_x conversion across a broad range from 150 to 400 掳C) to the traditional zeolite-based catalysts of Cu-Beta and Cu-ZSM-5. Furthermore, the opportune size of pore opening (鈭?.8 脜) made Cu-SSZ-13 exhibiting the best selectivity to N₂ as well as satisfactory tolerance toward SO₂ and C₃H₆ poisonings. The characterization (XRD, XPS, XRF, and H₂-TPR) of samples confirmed that Cu-SSZ-13 possessed the most abundant Cu cations among three investigated Cu-zeolites; furthermore, either on the surface or in the bulk the ratio of Cu⁺/Cu²⁺ ions for Cu-SSZ-13 is also the highest. New finding was announced that CHA-type topology is in favor of the formation of copper cations, especially generating much more Cu⁺ ions than the others, rather than CuO. The activity test of Cu(CuCl)-ZSM-5 (prepared by a solid-state ion-exchange method) clearly indicated that Cu⁺ ions could make a major contribution to the low-temperature deNO_x activity. The activity of protonic zeolites (H-SSZ-13, H-Beta, H-ZSM-5) revealed the topology effect on SCR performances.