Issue 25, 2013

Silica–alumina/sepiolite nanoarchitectures

Abstract

Novel silicaalumina/sepiolite nanoarchitectures have been prepared by an original approach based on sol–gel procedures. A commercial organo-sepiolite is used as a starting material whose organocations are provided by alkylchains that contribute to the controlled hydrolysis and polycondensation of silicon and aluminium alkoxides mixtures added to a non-aqueous suspension of that sepiolite. This procedure yields the coagulation of the alkoxides–organosepiolite suspension, resulting in the formation of a homogenous gel. After thermal treatment of the dried system, the organic matter is removed and the silica–alumina network consolidated. The characterization of the resulting materials reveals the formation of silicaalumina nanoparticles that remain anchored to the surface of sepiolite fibers through the silanol groups of the core silicate. These novel nanoarchitectures show specific surface areas in the range of 250–300 m2 g−1. The porosity of the resulting materials can be controlled depending on the nature of the oxide network generated. Thus, high silica contents generated microporous systems, whereas the incorporation of alumina enhances the mesoporous formation. The incorporation of a silica–alumina network on the surface sepiolite also permits the tuning of its surface acidity, typical values increasing from 0.1 to 1.4 mmol of acid sites per gram, according to the aluminium content. The acid–base properties of the new nanoarchitectures were evaluated as acid catalysts from the 2-propanol dehydration test. The catalytic behaviour is discussed in terms of the acidic properties of the involved solids.

Graphical abstract: Silica–alumina/sepiolite nanoarchitectures

Supplementary files

Article information

Article type
Paper
Submitted
30 Dec. 2012
Accepted
28 Marts 2013
First published
28 Marts 2013

J. Mater. Chem. A, 2013,1, 7477-7487

Silicaalumina/sepiolite nanoarchitectures

C. Belver, P. Aranda and E. Ruiz-Hitzky, J. Mater. Chem. A, 2013, 1, 7477 DOI: 10.1039/C3TA01686B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements