Chem. J. Chinese Universities ›› 2021, Vol. 42 ›› Issue (1): 133.doi: 10.7503/cjcu20200548

Special Issue: 分子筛功能材料 2021年,42卷,第1期

• Review • Previous Articles     Next Articles

Atomic Scale Structure of Beam Sensitive Materials

CHEN Xiao, SHEN Boyuan, XIONG Hao, WEI Fei()   

  1. Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology,Department of Chemical Engineering,Tsinghua University,Beijing 100084,China
  • Received:2020-08-10 Online:2021-01-10 Published:2021-01-12
  • Contact: WEI Fei E-mail:wf-dce@tsinghua.edu.cn
  • Supported by:
    ? Supported by the National Natural Science Foundation of China Major Research Program Cultivation(91434122);the National Natural Science Foundation of China(22005170)

Abstract:

Molecular sieves and metal organic framework (MOF) materials are widely used in the fields of catalysis, energy storage, drying, purification, and adsorption separation due to their unique pores and framework structures. The atomic scale characterization of their structures is significance for a deep understanding of their structure-activity relationships. However, their large pore structure and organic framework make them extremely sensitive to electron beam. The structure will be quickly destroyed and become amorphous in the conventional transmission electron microscope imaging mode, and the atomic arrangement information of the pores and framework cannot be obtained. The recently developed scanning transmission electron microscopy technology based on integrated differential phase contrast (iDPC-STEM) has shown obvious advantages in imaging of beam sensitive materials and light element components, making the characterization of porous framework materials and hydrocarbon pool species become possible. This article reviews our research group’s recent research on molecular sieve and MOF material atomic structure using this technology. The iDPC-STEM technology was applied to the ZSM-5 molecular sieve catalyst for methanol conversion to realize the imaging analysis of the atomic-level framework structure of the molecular sieve. In the MOF system, the coordination mode of the organic linker and the metal node in the MIL-101 framework was observed using this technology. On this basis, the benzene ring structure of the organic link and the metal node was analyzed, and the atomic-level surface, interface and defects and other local structural features of the MOF were observed. Finally, the application potential of iDPC-STEM technology in atomic scale imaging is summarized and prospected.

Key words: Transmission electron microscopy(TEM), Integrated differential phase contrast, Metal organic framework(MOF), Molecular sieve

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