The Effects of Ammonium Hexafluorosilicate Post-Treatment on the Acidity of H-ZSM-5 Zeolite Studied by Solid-State NMR Spectroscopy

  • Yong-xiang WANG ,
  • Qiang WANG ,
  • Jun XU ,
  • Qing-hua XIA ,
  • Feng DENG
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  • 1. Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Collaborative Innovation Center for Advanced Organic Chemical Materials Co-constructed by the Province and Ministry, Hubei University, Wuhan 430062, China
    2. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision, National Centre for Magnetic Resonance in Wuhan, Wuhan 430071, China

Received date: 2021-06-29

  Online published: 2021-08-26

Abstract

In this study, solid-state nuclear magnetic resonance (NMR) spectroscopy was used to probe the changes of acidity of H-ZSM-5 zeolite caused by ammonium hexafluorosilicate (AHFS) washing-related changes of aluminium species. It was observed that the four-coordinate framework aluminum species with Brønsted acidity were partially reduced, while the tri-coordinated framework aluminum with Lewis acidity was slightly decreased after the AHFS treatment. However, AHFS washing was also found to induce mild dealumination and a significant reduction of aluminum species with Lewis acidity containing Al-OH group on zeolites, thus resulting in a remarkable change in the overall acidity of the zeolites.

Cite this article

Yong-xiang WANG , Qiang WANG , Jun XU , Qing-hua XIA , Feng DENG . The Effects of Ammonium Hexafluorosilicate Post-Treatment on the Acidity of H-ZSM-5 Zeolite Studied by Solid-State NMR Spectroscopy[J]. Chinese Journal of Magnetic Resonance, 2021 , 38(4) : 514 -522 . DOI: 10.11938/cjmr20212927

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