催化作用
铜
选择性催化还原
硅醇
氨
化学
热液循环
结晶学
戒指尺寸
粒径
水热合成
Crystal(编程语言)
单晶
模板
戒指(化学)
人口
无机化学
化学工程
材料科学
有机化学
纳米技术
物理化学
工程类
计算机科学
程序设计语言
人口学
社会学
作者
Andreas Hoffmann,Michiel De Prins,Sreeprasanth Pulinthanathu Sree,Gina Vanbutsele,Sam Smet,C. Vinod Chandran,Sambhu Radhakrishnan,Eric Breynaert,Johan A. Martens
摘要
LEV type zeolites were synthesized with four different structure-directing agents and converted to copper loaded NH3-SCR catalysts. The synthesis recipe was found to impact the respective Al population in the two topologically different framework sites in double and single 6-rings, resolvable by 27Al MAS NMR spectroscopy. Hydrothermal stability was found to be related to the silanol concentration, Si/Al ratio, particle size, crystal morphology, crystal defects, external surface area, and microporosity. Catalytic activity in NH3-SCR was dependent on preferential Al siting in the double 6-rings. Levinite synthesized using adamantylamine showed the strongest preference for Al atoms sitting in double 6-ring sites, and showed the highest catalytic turnover frequency. Unfortunately, because of the large crystal size, copper loading of this sample was limited to 0.6 wt% while other samples could be loaded with copper up to 3.3 wt%. An optimum combination of hydrothermal stability and catalytic activity was obtained with N,N'-bis-dimethylpentanediyldiammonium dibromide as structure-directing agent.
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