Mountjoy, G. and Holland, M.A. and Gunawidjaja, P.N. and Pickup, D.M. and Wallidge, G.W. and Smith, M.E. and Newport, R.J. (2003) Transition metal atom sites in ternary ZrO2-TiO2-SiO2 xerogels. Journal of Sol-Gel Science and Technology, 26 (1-3). pp. 137-141. ISSN 0928-0707.
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There has been much work on the binary TiO2-SiO2 and ZrO2-SiO2 materials prepared by sol-gel because of the beneficial properties resulting from incorporation of Ti and Zr. In contrast the ternary TiO2-ZrO2-SiO2 xerogels have been relatively little studied. We report the results of a study of those xerogels having Zr:Ti:Si ratios of 5:15:80, 10:10:80 and 15:5:80 heated to 750degreesC and to 1000degreesC. The study includes X-ray diffraction, small angle X-ray scattering, X-ray absorption spectroscopy at Ti and Zr K-edges, and O-17 MAS-NMR. The study has benefited from close comparison with similar previous studies of the binary systems. The metal atoms in the ternary systems are shown to be predominantly homogeneously mixed in the silica network, as observed for the respective binary systems. The clear exception is for the sample with a minority of Zr, which after heat treatment at 750degreesC shows the presence of phase separation attributed to the formation of an amorphous precursor of ZrTiO4; at 1000degreesC this phase crystallises. In samples with higher Zr content the crystallisation of a ZrO2 tetragonal phase was observed. The data obtained illustrate well the strength of a research methodology in which a common batch of samples is studied using a coherent suite of modern structural probes.
|Uncontrolled keywords:||ternary mixed oxide xerogels; structure; EXAFS; XANES; MAS NMR ZIRCONIA-SILICA XEROGELS; ALKOXIDE SOLUTIONS; TI COORDINATION; TITANIA-SILICA; XANES; EXAFS|
Q Science > QC Physics
|Divisions:||Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group|
|Depositing User:||Bob Newport|
|Date Deposited:||26 Jun 2008 18:47|
|Last Modified:||22 May 2012 13:41|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/8216 (The current URI for this page, for reference purposes)|
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