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  Zeolite Beta Formation from Clear Sols: Silicate Speciation, Particle Formation and Crystallization Monitored by Complementary Analysis Methods

Castro, M., Haouas, M., Lim, I., Bongard, H.-J., Schüth, F., Taulelle, F., et al. (2016). Zeolite Beta Formation from Clear Sols: Silicate Speciation, Particle Formation and Crystallization Monitored by Complementary Analysis Methods. Chemistry – A European Journal, 22(43), 15307-15319. doi:10.1002/chem.201600511.

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 Creators:
Castro, Maria1, Author              
Haouas, Mohamed2, Author
Lim, Ivy3, Author              
Bongard, Hans-Josef4, Author              
Schüth, Ferdi3, Author              
Taulelle, Francis2, 5, Author
Karlsson, Gunnel6, Author
Alfredsson, Viveka7, Author
Breyneart, Eric5, Author
Kirschhock, Christine E. A.5, Author
Schmidt, W.1, Author              
Affiliations:
1Research Group Schmidt, Max-Planck-Institut für Kohlenforschung, Max Planck Society, ou_1445618              
2Institut Lavoisier de Versailles, University of Versailles, Versailles, France, ou_persistent22              
3Research Department Schüth, Max-Planck-Institut für Kohlenforschung, Max Planck Society, ou_1445589              
4Service Department Lehmann (EMR), Max-Planck-Institut für Kohlenforschung, Max Planck Society, ou_1445625              
5Center for Surface Chemistry and Catalysis, KU Leuven, Leuven, Belgium., ou_persistent22              
6National Center for High Resolution Electron Microscopy, Lund University, Lund, Sweden., ou_persistent22              
7Division of Physical Chemistry, KILU, Lund University, Lund, Sweden., ou_persistent22              

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Free keywords: clear sols, transmission electron microscopy, crystal growth, mass spectrometry, nanoparticles, NMR spectroscopy, oligomers, small angle scattering, zeolites
 Abstract: The formation of silicate nanoaggregates (NAs) at the very early stages of precursor sols and zeolite beta crystallization from silicate nanoparticles (NPs) are investigated in detail using a combination of different analysis methods, including liquid-state 29Si, 27Al, 14N, and 1H NMR spectroscopy, mass spectrometry (MS), small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), and transmission electron microscopy at cryogenic temperatures (cryo-TEM). Prior to hydrothermal treatment, silicate NAs are observed if the Si/OH ratio in the reaction mixture is greater than 1. Condensation of oligomers within the NAs then generates NPs. Aluminum doped into the synthesis mixtures is located exclusively in the NPs, and is found exclusively in a state that is fourfold connected to silicate, favoring their condensation and aggregation. These results are in agreement with general trends observed for other systems. Silicate NAs are essential intermediates for zeolite formation and are generated by the aggregation of hydrated oligomers, aluminate, and templating cations. Subsequent further intra-nanoaggregate silicate condensation results in the formation of NPs. 1H and 14N liquid NMR as well as diffusion ordered spectroscopy (DOSY) experiments provide evidence for weakly restricted rotational and translational mobility of the organic template within NAs as a consequence of specific silicate–template interactions. NAs thus appear as key species in clear sols, and their presence in the precursor sol favors silicate condensation and further crystallization, promoted either by increasing the Si/OH ratio or by heating.

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Language(s): eng - English
 Dates: 2016-09-072016-10-17
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1002/chem.201600511
 Degree: -

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Title: Chemistry – A European Journal
  Other : Chem. – Eur. J.
  Other : Chem. Eur. J.
Source Genre: Journal
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Publ. Info: Weinheim, Germany : VCH Verlagsgesellschaft
Pages: - Volume / Issue: 22 (43) Sequence Number: - Start / End Page: 15307 - 15319 Identifier: ISSN: 0947-6539
CoNE: https://pure.mpg.de/cone/journals/resource/954926979058