In-situ high-temperature XANES observations of rapid and reversible changes in Ti coordination in titania-silica xerogels

Mountjoy, G. and Pickup, D.M. and Wallidge, G.W. and Cole, J.M. and Newport, R.J. and Smith, M.E. (1999) In-situ high-temperature XANES observations of rapid and reversible changes in Ti coordination in titania-silica xerogels. Chemical Physics Letters, 304 (3-4). pp. 150-154. ISSN 0009-2614. (Access to this publication is restricted)

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Abstract

The height and position of the pre-edge peak in Ti K-edge X-ray absorption near-edge structure (XANES) is a sensitive indicator of the coordination of Ti. This method is used in situ to investigate Ti coordination in titania-silica xerogels with low TiO2 content. Unheated xerogels contain Ti with isolated, distorted 6-fold coordination (Ti-[6]). Initial heating causes [Ti-[6] to be rapidly converted into 4-fold coordinated Ti(Ti-[4]), which upon cooling reverts to Ti-[6]. Increased heat treatment creates more stable Ti-[4], which remains after cooling. Thus, the coordination of Ti depends on ambient conditions in addition to heat treatment. In-situ XANES is important for distinguishing different kinds of Ti-[4], and hence for understanding catalytic properties. (C) 1999 Elsevier Science B.V. All rights reserved.

Item Type: Article
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group
Depositing User: I.T. Ekpo
Date Deposited: 05 Apr 2009 19:52
Last Modified: 24 Apr 2012 13:28
Resource URI: http://kar.kent.ac.uk/id/eprint/16948 (The current URI for this page, for reference purposes)
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