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

Analysis of Polymorphic Nanocrystals of TiO2 by X-Ray Rietveld Refinement and High-Resolution Transmission Electron Microscopy: Acetaldehyde Decomposition

R. Carrera,1,2 N. Castillo,2 E. Arce,2 A. L. Vázquez,1,2 M. Moran-Pineda,1 J. A. Montoya,1 P. Del Ángel,1 and S. Castillo1,2

 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

Recommended by Lyudmila Bronstein

Abstract

In this work, TiO2 nanocrystals were synthesized by the sol-gel method. These materials were annealed at 200 and 500∘C; and characterized by the XRD-Rietveld refinement; and by BET and TEM. As for the low-temperature-treated sample (200∘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 500∘C showed an increased crystallite size (22 nm) and an important polymorphic increment. The sample annealed at 200∘C showed a high activity in the photocatalytic decomposition of acetaldehyde.