Structure Solution and Defect Analysis of an Extra-Large Pore Zeolite with UTL Topology by Electron Microscopy
Structure Solution and Defect Analysis of an Extra-Large Pore Zeolite with UTL Topology by Electron Microscopy
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UTL拓扑超大孔沸石电子显微镜结构解析及缺陷分析
DOI：
10.1021/acs.jpclett.0c00551
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发表时间：
2020-05-07
影响因子：
5.7
通讯作者：
Mayoral, Alvaro
中科院分区：
文献类型：
--
作者：
Li, Junyan;Zhang, Chuanqi;Mayoral, Alvaro
沸石中的缺陷对于解释其物理化学行为至关重要。具有柱撑层结构的UTL沸石已被广泛应用于沸石晶体工程中，以从其层状结构单元组装新的结构，但对其缺陷缺乏基本的了解。在这里，我们报告了一种新合成的UTL骨架沸石，UTL-DBU，与商业上可获得的超强碱1，8-二氮杂双环[5.4.0]十一碳-7-烯（DBU）作为模板剂。它的结构是由三维电子衍射断层扫描和高分辨率（扫描）透射电子显微镜相结合。用透射电子显微镜观察，发现了两种类型的缺陷：堆垛层错和类刃位错平面缺陷。在电子衍射和成像分析的基础上，成功地建立了微孪晶的层堆积序列、结构模型和数学模型。解开这些缺陷将提供新的见解，利用UTL的目标沸石的合理设计。
Defects within zeolites are crucially important for explaining their physicochemical behavior. The UTL zeolite, with a pillared layer structure, has been widely used in zeolite crystal engineering to assemble new structures from its layered structural units, but a fundamental understanding of its defect is lacking. Here, we report a newly synthesized UTL framework zeolite, UTL-DBU, with a commercially available superbase 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a template. Its structure was determined by a combination of three-dimensional electron diffraction tomography and high-resolution (scanning) transmission electron microscopy. Using transmission electron microscopy, two types of defects, stacking disorder and edge dislocation-like planar defect, were discovered. On the basis of the analysis of the electron diffraction and imaging, the layer stacking sequence together with the structural and mathematical models of the microtwinning was successfully built up. Unraveling these defects will provide new insights into the rational design of targeted zeolites utilizing UTL.