Spectroscopic characterisation of mixed titania-silica xerogel catalysts

Holland, M.A. and Pickup, D.M. and Mountjoy, G. and Tsang, S.C and Wallidge, G.W. and Newport, R.J. and Smith, M.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: 06 Sep 2011 01:59
Resource URI: http://kar.kent.ac.uk/id/eprint/16226 (The current URI for this page, for reference purposes)
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