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Acid Catalysis over Low-Silica Faujasite Zeolites

Li, Xinyu and Han, He and Xu, Wenqian and Hwang, Son-Jong and Shi, Zhichen and Lu, Peng and Bhan, Aditya and Tsapatsis, Michael (2022) Acid Catalysis over Low-Silica Faujasite Zeolites. Journal of the American Chemical Society, 144 (21). pp. 9324-9329. ISSN 0002-7863. doi:10.1021/jacs.2c01022.

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Low-silica faujasite (FAU) zeolites (with Si/Al ratio of ca. 1.2–1.8) sustain framework integrity and porosity upon moderate ion exchange (0.01 M NH₄NO₃ solution for 1 h at ambient temperature), which introduces two kinds of protons, distinctive in reactivity and coordination to the zeolite framework, within supercages (HSUP). Moderate ion exchange limited within supercages transpires while maintaining full occupancy of Na⁺ cations within associated sodalite cages; this in turn helps stabilize the framework of low-silica H-FAU zeolites. Protons located on site II (H₃₆₃₀) and site III (H₃₆₅₀) within supercages on low-silica FAU zeolites can be classified and enumerated by virtue of infrared spectroscopy, providing an opportunity to compare reactivities of these distinct protons for monomolecular protolytic reactions of propane. Protons on site II exhibit prominently higher reactivity for monomolecular propane dehydrogenation and cracking than protons on site III. Low-silica proton-form FAU zeolites (zeolite X) upon moderate ion exchange possess protons on site III that are unavailable on high-silica FAU zeolites (zeolite Y) and limit ion exchange within supercages, providing unprecedented high-temperature structural and chemical stability (>773 K) and enabling their application as solid-acid catalysts.

Item Type:Article
Related URLs:
URLURL TypeDescription
Han, He0000-0001-6012-4126
Hwang, Son-Jong0000-0002-3210-466X
Shi, Zhichen0000-0001-9839-763X
Lu, Peng0000-0002-9773-3993
Bhan, Aditya0000-0002-6069-7626
Tsapatsis, Michael0000-0001-5610-3525
Additional Information:© 2022 American Chemical Society. Received: January 27, 2022; Published: May 17, 2022. We acknowledge partial support from the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences under Award No. DE-SC0001004. Partial support was also provided by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences (Award DE-FG02-12ER16362), and by the U.S. Department of Energy, Office of Basic Energy Science, Catalysis Science Program (Award DE-SC00019028). Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial NSF support through the MRSEC and NNIN programs (DMR-1420013). Solid-state MAS NMR measurements were provided by the NMR facility at Caltech. The synchrotron XRD data were collected through the mail-in program at Beamline 17-BM of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility, operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. The authors also thank the reviewers for their helpful technical suggestions during the revision of this manuscript. The authors declare no competing financial interest.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0001004
Department of Energy (DOE)DE-FG02-12ER16362
Department of Energy (DOE)DE-SC00019028
Department of Energy (DOE)DE-AC02-06CH11357
Subject Keywords:Cations, Deformation, Ion exchange, Organic reactions, Zeolites
Issue or Number:21
Record Number:CaltechAUTHORS:20220519-607820000
Persistent URL:
Official Citation:Acid Catalysis over Low-Silica Faujasite Zeolites. Xinyu Li, He Han, Wenqian Xu, Son-Jong Hwang, Zhichen Shi, Peng Lu, Aditya Bhan, and Michael Tsapatsis. Journal of the American Chemical Society 2022 144 (21), 9324-9329; DOI: 10.1021/jacs.2c01022
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114818
Deposited By: George Porter
Deposited On:20 May 2022 16:14
Last Modified:08 Jun 2022 16:46

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