Title: Investigation of the Mechanism of Colloidal Silicalite-1 Crystallization by Using DLS, SAXS, and Si-29 NMR Spectroscopy
Authors: Aerts, Alexander ×
Haouas, Mohamed
Caremans, Tom
Follens, Lana
Van Erp, Titus
Taulelle, Francis
Vermant, Jan
Martens, Johan
Kirschhock, Christine #
Issue Date: 2010
Publisher: Wiley-v c h verlag gmbh
Series Title: Chemistry-a european journal vol:16 issue:9 pages:2764-2774
Abstract: Colloidal silicalite-1 zeolite was crystallized from a concentrated clear sol prepared from tetraethylorthosilicate (TEOS) and aqueous tetra-propylammonium hydroxide (TPAOH) solution at 95 degrees C. The silicate speciation was monitored by using dynamic light scattering (DLS), synchrotron small-angle X-ray scattering (SAXS), and quantitative liquid-state Si-29 NMR spectroscopy. The silicon atoms were present in dissolved oligomers, two discrete nanoparticle populations approximately 2 and 6 nm in size, and crystals. On the basis of new insight into the evolution of the different nanoparticle populations and of the silicate connectivity in the nanoparticles, a refined crvstallization mechanism was derived. Upon combining the reagents, different types of nanoparticles (ca. 2 nm) are formed. A fraction of these nanoparticles with the least condensed silicate structure does not participate in the crystallization process. After completion of the crystallization, they represent the residual silicon atoms. Nanoparticles with a more condensed silicate network grow until approximately 6 nm and evolve into building blocks for nucleation and growth of the silicalite-1 crystals. The silicate network connectivity of nanoparticles suitable for nucleation and growth increasingly resembles that of the final zeolite. This new insight into the two classes of nanoparticles will be useful to tune the syntheses of silicalite-1 for maximum yield.
ISSN: 0947-6539
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Soft Matter, Rheology and Technology Section
Centre for Surface Chemistry and Catalysis
× corresponding author
# (joint) last author

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