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SEM and Raman study of thermally treated TiO2 anatase nanopowders: influence of calcination on photocatalytic activity

Mahdjoub, N. and Allen, Norman S. and Kelly, Peter and Vishnyakov, Vladimir (2010) SEM and Raman study of thermally treated TiO2 anatase nanopowders: influence of calcination on photocatalytic activity. ISSN 1873-2666

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Abstract

Titania (TiO2) nanopowders called PC 500, synthesised by the sulphate process, were annealed in air at temperatures of up to 1022 K for 30 min. The X-ray Diffraction (XRD) indicates that the thermal annealing resulted in coarsening of the average crystallite size from 13 to 72 nm. However, Scanning Electron Microscopy (SEM) reveals persistence of platelet-like structures which survive up to temperatures around 900 K. This implies that the crystals at least partially grow within the plates in 2D confinement. This implies that direct usage of Scherrer equation in this case should be approached with care. Raman spectra peak positions and the Full-Width-at-Half-Maximum (FWHM) values changed considerably after calcinations crystal growth, while, material composition and oxygen content remain unchanged. The Raman peak behaviour can be cautiously attributed to the first order phonon confinement phenomena, but both, 2D and 3D models of confinement should be accounted. The highest photoactivity, as indicated by photoinduced degradation of a mono azo dye methyl-orange (C14H14N3SO3Na), was observed in material treated at 773 K.

Item Type: Article
Additional Information: Full-text of this article is not available in this e-prints service. This article was originally published following peer-review in Journal of Photochemistry and Photobiology, A: Chemistry, published by and copyright Elsevier.
Divisions: Legacy Research Institutes > Dalton Research Institute > Material Science
Date Deposited: 04 Aug 2010 15:02
Last Modified: 01 Sep 2016 14:02
URI: http://e-space.mmu.ac.uk/id/eprint/109075

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