Advanced

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

Castro, Maria; Haouas, Mohamed; Lim, Ivy; Bongard, Hans J.; Schüth, Ferdi; Taulelle, Francis; Karlsson, Gunnel LU ; Alfredsson, Viveka LU ; Breyneart, Eric and Kirschhock, Christine E A, et al. (2016) In Chemistry - A European Journal 22(43). p.15307-15319
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... (More)

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.

(Less)
Please use this url to cite or link to this publication:
author
, et al. (More)
(Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
clear sols, crystal growth, mass spectrometry, nanoparticles, NMR spectroscopy, oligomers, small angle scattering, transmission electron microscopy, zeolites
in
Chemistry - A European Journal
volume
22
issue
43
pages
13 pages
publisher
John Wiley & Sons
external identifiers
  • scopus:84987667428
  • wos:000384807600001
ISSN
0947-6539
DOI
10.1002/chem.201600511
language
English
LU publication?
yes
id
09608db4-1458-45fb-a01f-5df2ee65190e
date added to LUP
2016-10-20 14:34:35
date last changed
2017-11-14 09:49:47
@article{09608db4-1458-45fb-a01f-5df2ee65190e,
  abstract     = {<p>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 <sup>29</sup>Si, <sup>27</sup>Al, <sup>14</sup>N, and <sup>1</sup>H 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. <sup>1</sup>H and <sup>14</sup>N 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.</p>},
  author       = {Castro, Maria and Haouas, Mohamed and Lim, Ivy and Bongard, Hans J. and Schüth, Ferdi and Taulelle, Francis and Karlsson, Gunnel and Alfredsson, Viveka and Breyneart, Eric and Kirschhock, Christine E A and Schmidt, Wolfgang},
  issn         = {0947-6539},
  keyword      = {clear sols,crystal growth,mass spectrometry,nanoparticles,NMR spectroscopy,oligomers,small angle scattering,transmission electron microscopy,zeolites},
  language     = {eng},
  month        = {10},
  number       = {43},
  pages        = {15307--15319},
  publisher    = {John Wiley & Sons},
  series       = {Chemistry - A European Journal},
  title        = {Zeolite Beta Formation from Clear Sols : Silicate Speciation, Particle Formation and Crystallization Monitored by Complementary Analysis Methods},
  url          = {http://dx.doi.org/10.1002/chem.201600511},
  volume       = {22},
  year         = {2016},
}