Synthesis, characterisation and performance of (TiO2)(0.18)(SiO2)(0.82) xerogel catalysts

Holland, Mark A. and Pickup, David M. and Mountjoy, Gavin and Tsang, Edman S. C. and Wallidge, Graham and Newport, Robert J. and Smith, Mark E. (2000) Synthesis, characterisation and performance of (TiO2)(0.18)(SiO2)(0.82) xerogel catalysts. Journal of Materials Chemistry, 10 (11). pp. 2495-2501. ISSN 0959-9428. (Full text available)

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http://dx.doi.org/10.1039/b005408i

Abstract

The synthesis of high surface area xerogels has been achieved using the sol-gel route. Heptane washing was used during the stages of drying to minimise capillary pressures and hence preserve pore structure and maximise the surface area. SAXS data have identified that heptane washing during drying, in general, results in a preservation of the pore structure and surface areas of up to 450 m(2) g(-1). O-17 NMR showed that Ti is fully mixed into the silica network in all of the samples. XANES data confirm that reversible 4-fold Ti sites are more prevalent in samples with high surface areas, as expected. The calcined xerogels were tested for their catalytic activity using the epoxidation of cyclohexene with tert-butyl hydroperoxide (TBHP) as a test reaction, with excellent selectivities and reasonable percentage conversions. FT-IR spectroscopy has revealed that the catalytic activity is correlated with the intensity of the Si-O-Ti signal, after accounting for variations in Si-OH and Si-O-Si. The most effective catalyst was produced with heptane washing, a calcination temperature of 500 degreesC, and a heating rate of 5 degreesC min(-1).

Item Type: Article
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group
Depositing User: O.O. Odanye
Date Deposited: 03 Apr 2009 09:58
Last Modified: 22 May 2014 11:14
Resource URI: http://kar.kent.ac.uk/id/eprint/16224 (The current URI for this page, for reference purposes)
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