Genesis and Stability of Hydronium Ions in Zeolite Channels

Meng Wang, Nicholas R. Jaegers, Mal Soon Lee, Chuan Wan, Jian Zhi Hu, Hui Shi, Donghai Mei, Sarah D. Burton, Donald M. Camaioni, Oliver Y. Gutiérrez, Vassiliki Alexandra Glezakou, Roger Rousseau, Yong Wang, Johannes A. Lercher

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15 Citations (Scopus)

Abstract

The catalytic sites of acidic zeolite are profoundly altered by the presence of water changing the nature of the Brønsted acid site. High-resolution solid-state NMR spectroscopy shows water interacting with zeolite Brønsted acid sites, converting them to hydrated hydronium ions over a wide range of temperature and thermodynamic activity of water. A signal at 9 ppm was observed at loadings of 2-9 water molecules per Brønsted acid site and is assigned to hydrated hydronium ions on the basis of the evolution of the signal with increasing water content, chemical shift calculations, and the direct comparison with HClO 4 in water. The intensity of 1 H- 29 Si cross-polarization signal first increased and then decreased with increasing water chemical potential. This indicates that hydrogen bonds between water molecules and the tetrahedrally coordinated aluminum in the zeolite lattice weaken with the formation of hydronium ion-water clusters and increase the mobility of protons. DFT-based ab initio molecular dynamics studies at multiple temperatures and water concentrations agree well with this interpretation. Above 140 °C, however, fast proton exchange between bridging hydroxyl groups and water occurs even in the presence of only one water molecule per acid site.

Original languageEnglish
Pages (from-to)3444-3455
Number of pages12
JournalJournal of the American Chemical Society
Volume141
Issue number8
DOIs
Publication statusPublished - Feb 27 2019

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ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Wang, M., Jaegers, N. R., Lee, M. S., Wan, C., Hu, J. Z., Shi, H., Mei, D., Burton, S. D., Camaioni, D. M., Gutiérrez, O. Y., Glezakou, V. A., Rousseau, R., Wang, Y., & Lercher, J. A. (2019). Genesis and Stability of Hydronium Ions in Zeolite Channels. Journal of the American Chemical Society, 141(8), 3444-3455. https://doi.org/10.1021/jacs.8b07969