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Enhanced Reactivity of Accessible Protons in Sodalite Cages of Faujasite Zeolite

Li, Xinyue and Han, He and Xu, Wenqian and Hwang, Son-Jong and Lu, Peng and Bhan, Aditya and Tsapatsis, Michael (2022) Enhanced Reactivity of Accessible Protons in Sodalite Cages of Faujasite Zeolite. Angewandte Chemie International Edition, 61 (5). Art. No. e202111180. ISSN 1433-7851. doi:10.1002/anie.202111180. https://resolver.caltech.edu/CaltechAUTHORS:20211207-6368000

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Abstract

Faujasite (FAU) zeolites (with Si/Al ratio of ca. 1.7) undergo mild dealumination at moderate ion exchange conditions (0.01 to 0.6 M of NH₄NO₃ solutions) resulting in protons circumscribed by sodalite cages becoming accessible for reaction without conspicuous changes to bulk crystallinity. The ratio of protons in sodalite cages (H_(SOD)) to supercages (H_(SUP)) can be systematically manipulated from 0 to ca. 1 by adjusting ammonium concentrations used in ion exchange. The fraction of accessible protons in the sodalite cages is assessed by virtue of infrared spectra for H-D exchange of deuterated propane based on the band area ratio of OD_(2620)/OD_(2680) (OD_(SOD)/OD_(SUP)). Protons in sodalite cages (H_(SOD)) show higher rate constants of propane dehydrogenation (k_D) and cracking (k_C) than protons in supercages (H_(SUP)) plausibly due to confinement effects being more prominent in smaller voids. Rate constants of dehydrogenation and cracking including k_D/k_C ratios are also augmented as the fraction of accessible protons in the sodalite cages is enhanced. These effects of accessibility and reactivity of protons in sodalite cages hitherto inconspicuous are revealed herein via methods that systematically increase accessibility of cations located in sodalite cages.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1002/anie.202111180DOIArticle
ORCID:
AuthorORCID
Li, Xinyue0000-0002-0822-4960
Hwang, Son-Jong0000-0002-3210-466X
Lu, Peng0000-0002-9773-3993
Bhan, Aditya0000-0002-6069-7626
Tsapatsis, Michael0000-0001-5610-3525
Additional Information:© 2021 Wiley-VCH GmbH. Issue Online: 18 January 2022; Version of Record online: 17 December 2021; Accepted manuscript online: 12 November 2021; Manuscript received: 18 August 2021. 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). Partial support was also provided by the US 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 support from the NSF 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 declare no conflict of interest.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0001004
Department of Energy (DOE)DE-FG02-12ER16362
Department of Energy (DOE)DE-SC00019028
NSFDMR-1420013
Department of Energy (DOE)DE-AC02-06CH11357
Subject Keywords:accessible sodalite cage; confinement effect; dealumination; faujasite; ion exchange
Issue or Number:5
DOI:10.1002/anie.202111180
Record Number:CaltechAUTHORS:20211207-6368000
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20211207-6368000
Official Citation:Enhanced Reactivity of Accessible Protons in Sodalite Cages of Faujasite Zeolite. X. Li, H. Han, W. Xu, S.-J. Hwang, P. Lu, A. Bhan, M. Tsapatsis, Angew. Chem. Int. Ed. 2022, 61, e202111180; DOI: 10.1002/anie.202111180
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112273
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:10 Dec 2021 20:58
Last Modified:19 Jan 2022 17:21

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