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Research Letters in Nanotechnology
Volume 2008 (2008), Article ID 138468, 5 pages
http://dx.doi.org/10.1155/2008/138468
Research Letter

Analysis of Polymorphic Nanocrystals of T i O 2 by X-Ray Rietveld Refinement and High-Resolution Transmission Electron Microscopy: Acetaldehyde Decomposition

1Programa de Ingeniería Molecular, Instituto Mexicano del Petróleo, 07730 México, D.F., Mexico
2Departamento de Ingeniería Metalúrgica, Escuela Superior de Ingeniería Química e Industrias Extractivas (ESIQIE), Instituto Politecnico Nacional (IPN), AP. 75-876, México 07300, Mexico

Received 13 January 2008; Accepted 23 May 2008

Academic Editor: Lyudmila Bronstein

Copyright © 2008 R. Carrera et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In this work, T i O 2 nanocrystals were synthesized by the sol-gel method. These materials were annealed at 200 and 5 0 0 C; and characterized by the XRD-Rietveld refinement; and by BET and TEM. As for the low-temperature-treated sample ( 2 0 0 C), nanocrystals with small crystallite sizes (7 nm) and high abundance of anatase, coexisting with the brookite phase, were obtained. Meanwhile, the sample annealed at 5 0 0 C showed an increased crystallite size (22 nm) and an important polymorphic increment. The sample annealed at 2 0 0 C showed a high activity in the photocatalytic decomposition of acetaldehyde.