Spectroscopic characterisation of mixed titania-silica xerogel catalysts

Holland, Mark A. and Pickup, David M. and Mountjoy, Gavin and Tsang, S.C and Wallidge, Graham and Newport, Robert J. and Smith, Mark E. (2000) Spectroscopic characterisation of mixed titania-silica xerogel catalysts. In: Symposium on Applications of Synchrotron Radiation Techniques to Materials Science V held at the 1999 MRS Fall Meeting, 29 November - 3 December 1999, Boston, Ma. (Access to this publication is restricted)

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Abstract

The synthesis of high surface area (TiO2)(0.18)(SiO2)(0.82) xerogels has been achieved using the sol-gel route. Heptane washing was used before the drying stage to minimise capillary pressure and hence preserve pore structure and maximise the surface area. The as-prepared xerogels were tested for their catalytic activity using the epoxidation of cyclohexene with tert-butyl hydrogen peroxide (TBHP) as a test reaction. Surface areas up to 450 m(2)g(-1) were achieved with excellent selectivities and reasonable percent conversions. SAXS data has identified that heptane washing during drying, in general, results in a preservation of the pore structure, and produces more effective catalysts with higher surface areas and larger pore diameters. FT-IR spectroscopy has revealed that the catalytic activity is dependant upon the number of Si-O-Ti linkages, inferring intimate mixing of the precursors at the atomic level. XANES data reveals the presence of reversible 4/6-fold Ti sites that are thought to be 'active' catalytic sites. The most effective catalyst was produced with a calcination temperature of 500 degrees C, and a heating rate of 5 degrees Cmin(-1).

Item Type: Conference or workshop item (Paper)
Additional information: Proceedings Paper Conference Information: Symposium on Applications of Synchrotron Radiation Techniques to Materials Science V held at the 1999 MRS Fall Meeting BOSTON, MA, NOV 29-DEC 03, 1999 Mat Res Soc; Blake Ind; Lawrence Livermore Natl Lab, Chem & Mat Sci Dept; NO Illinois Univ, Grad Sch & Coll Liberal Arts & Sci
Subjects: Q Science > QC Physics
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences
Depositing User: O.O. Odanye
Date Deposited: 03 Apr 2009 09:50
Last Modified: 22 May 2014 11:13
Resource URI: http://kar.kent.ac.uk/id/eprint/16226 (The current URI for this page, for reference purposes)
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