Ali, F. and Chadwick, A.V. and Smith, M.E. (1997) EXAFS analysis of the structural evolution of gel-formed La2O3. Journal of Materials Chemistry, 7 (2). pp. 285-291. ISSN 0959-9428.
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Sol-gel-produced La2O3, derived from the hydrolysis and subsequent calcination of lanthanum isopropoxide, has been investigated by EXAFS of the La L(III) edge. The evolution of the local structure through a series of amorphous intermediate states has been modelled by three shells, two lanthanum-oxygen and the other lanthanum-lanthanum. For comparison, well characterised bulk La(OH)(3), LaO(OH) and La2O3 were examined using EXAFS. The sol-gel-prepared oxide was more disordered and had significantly smaller particles than the oxide prepared by calcination of La-2(CO3)(3) after the same heat treatments. For the gels in the intermediate states, well defined La-O shells are seen but the La-La shells are characterised by large Debye-Waller factors. Comparison of these results with previous O-17 solid-state NMR on a similar set of samples has some significant implications for the sensitivity to disorder of these important atomic-scale probes.
|Depositing User:||T. Nasir|
|Date Deposited:||29 Oct 2009 19:00|
|Last Modified:||29 Oct 2009 19:00|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/18256 (The current URI for this page, for reference purposes)|
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