Chinese Journal of Catalysis ›› 2019, Vol. 40 ›› Issue (12): 1854-1859.DOI: 10.1016/S1872-2067(19)63287-0

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Interzeolite transformation from FAU to CHA and MFI zeolites monitored by UV Raman spectroscopy

Juan Zhanga, Yueying Chuc, Xiaolong Liud, Hao Xua, Xiangju Mengb, Zhaochi Fenga, Feng-Shou Xiaoa   

  1. a Department of Chemistry, Key Lab of Applied Chemistry of Zhejiang Province, Zhejiang University, Hangzhou 310028, Zhejiang, China;
    b State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China;
    c State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, Hubei, China;
    d School of Materials Science and Engineering, Sun Yat-Sun University, Guangzhou 510275, Guangdong, China
  • Received:2019-01-10 Revised:2019-02-25 Online:2019-12-18 Published:2019-09-21
  • Supported by:
    This work was supported by the National Key R&D Program of China (2017YFB0702800), the National Natural Science Foundation of China (2152780065, 91634201 and 21720102001), and the Strategic Priority Research Program of Chinese Academy of Sciences (XDB17000000).

Abstract: As a powerful and sensitive tool for the characterization of zeolite building units, UV Raman spectroscopy has been used to monitor interzeolite transformation from FAU to CHA and MFI zeolites. The results show that the behavior of double 6-membered rings (D6Rs) in the FAU zeolite framework plays an important role during the formation of the target product in the interzeolite transformation. For the transformation of FAU to CHA, because both zeolites contain the same D6R units, direct transformation occurs, in which the D6Rs were largely unchanged. In contrast, for the transformation of FAU to MFI, the D6Rs can be divided into two single 6-membered rings (S6Rs), which further assembled into the MFI structure. In this crystallization, 5-membered rings (5Rs) are only observed in the MFI framework formation, suggesting that the basic building units in the transformation of FAU to MFI are S6Rs rather than 5Rs. These insights will be helpful for further understanding of the interzeolite transformation.

Key words: Interzeolite transformation, UV Raman spectroscopy, DFT calculation, Double 6-memberred rings, Decomposition and re-assembly