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Spectroscopic Characterization of Mixed Titania-Silica Xerogel Catalysts

Published online by Cambridge University Press:  10 February 2011

MA Holland ,
DM Pickup ,
G Mountjoy ,
SC Tsang ,
GW Wallidge ,
RJ Newport  and
ME Smith
MA Holland
Affiliation:
contact author: mah3@ukc.ac.uk
DM Pickup
Affiliation:
School of Physical Sciences, University of Kent at Canterbury, CT2 7NR, UK.
G Mountjoy
Affiliation:
School of Physical Sciences, University of Kent at Canterbury, CT2 7NR, UK.
SC Tsang
Affiliation:
Centre for Catalysis, Department of Chemistry, University of Reading, RG6 6AD, UK.
GW Wallidge
Affiliation:
Department of Physics, University of Warwick, Coventry, CV4 7AL, UK.
RJ Newport
Affiliation:
School of Physical Sciences, University of Kent at Canterbury, CT2 7NR, UK.
ME Smith
Affiliation:
Department of Physics, University of Warwick, Coventry, CV4 7AL, UK.
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Abstract

The synthesis of high surface area (TiO2)0.18(SiO2)0.82xerogels 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 m2g-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. Fr-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°C, and a heating rate of 5 °Cmin-l

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 590: Symposium R – Applications of Synchrotron Radiation Techniques…V , 1999 , 77
Copyright
Copyright © Materials Research Society 2000

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References

REFERENCES

[1] Itoh, M., Hattori, H. and Tanabe, K. J., J. Catalysis, 225, 35, 1974.Google Scholar
[2] Jorgensensen, K. A., American Chem. Soc., 89, 3, 1989.Google Scholar
[3] Mountjoy, G., Pickup, D. M., Wallidge, G. W., Anderson, R., Cole, J. M., Newport, R. J. and Smith, M. E., Chem. Mater., 11, 5, 1999.10.1021/cm980644uGoogle Scholar
[4] Anderson, R., Mountjoy, G., Smith, M. E. and Newport, R. J., J Non-Cryst. Solids, 232–234, 72–79, 1998.10.1016/S0022-3093(98)00373-1Google Scholar
[5] Pickup, D. M., Mountjoy, G., Wallidge, G. W., Anderson, R., Cole, J. M., Newport, R. J. and Smith, M. E., J. Mat. Chem., 1299, 9, 1999.Google Scholar
[6] Yoldas, B. E., J.Non-Cryst. Solids, 81, 38, 1980.Google Scholar
[7] Schraml-Marth, M., Walther, M., Wokaun, K. L., Handy, B. E. and Baiker, A., J. Non-Cryst. Solids, 47, 143, 1991..Google Scholar
[8] Hutter, R., Mallat, T. and Baiker, A., Journal Catal., 177-189, 153, 1995.Google Scholar
[9] Smith, M.E. and Whitfield, H. J., J. Chem. Soc., Chem. Commun., 723, 1994.Google Scholar
[10] Schmidt, P.W., J. Appl. Cryst., 414, 24, 1991.Google Scholar