Structural investigation of alumina silica mixed oxide gels prepared from organically modified precursors

Author(s)

Herwig Peterlik, Harald Rennhofer, Viktoria Torma, Ulrike Bauer, Michael Puchberger, Nicola Hüsing, Sigrid Bernstorff, Ulrich Schubert

Abstract

The development of the structure of silica/alumina gels was investigated by small angle X-ray scattering (SAXS) through all stages of the preparation process, that is gelation, aging, drying and calcination. Two series of gels were compared; the first was prepared from a single-source precursor, obtained by reaction of 3-oxoethyl-6-trimethoxysilyl-hexan-2-one (OTH-H) with Al(OsBu)3. The gels of the second series were prepared from the same precursors, but under conditions where hydrodeacylation of OTH-H occurs. It turned out that both series showed a similar structural development of the gels. Immediately after the start of the reaction small primary particles are formed, the size of which (r = 0.7 ± 0.1 nm) remains constant through the gelation and aging process. In some samples, Si(OEt)4 was added as an additional source for Si/O which was incorporated between the primary particles. Condensation proceeds by a slower aggregation of the primary particles, which initially form a rather open network. This network densifies during aging and drying. © 2007 Elsevier B.V. All rights reserved.

Organisation(s)

Dynamics of Condensed Systems

External organisation(s)

Technische Universität Wien, Universität Ulm, Elettra─Sincrotrone Trieste

Journal

Journal of Non-Crystalline Solids

Volume

353

Pages

1635-1644

No. of pages

10

ISSN

0022-3093

DOI

https://doi.org/10.1016/j.jnoncrysol.2007.01.016

Publication date

2007

Peer reviewed

Yes

Austrian Fields of Science 2012

104003 Inorganic chemistry, 1030 Physics, Astronomy

Portal url

https://ucrisportal.univie.ac.at/en/publications/4a5ab35a-f159-4828-adcd-d58605cfcaad