title: Phase-pure TiO(2) nanoparticles: anatase, brookite and rutile.
abstract: We report on the synthesis of phase-pure TiO(2) nanoparticles in anatase, rutile and brookite structures, using amorphous titania as a common starting material. Phase formation was achieved by hydrothermal treatment at elevated temperatures with the appropriate reactants. Anatase nanoparticles were obtained using acetic acid, while phase-pure rutile and brookite nanoparticles were obtained with hydrochloric acid at a different concentration. The nanomaterials were characterized using x-ray diffraction, UV-visible reflectance spectroscopy, dynamic light scattering, and transmission electron microscopy. We propose that anatase formation is dominated by surface energy effects, and that rutile and brookite formation follows a dissolution-precipitation mechanism, where chains of sixfold-coordinated titanium complexes arrange into different crystal structures depending on the reactant chemistry. The particle growth kinetics under hydrothermal conditions are determined by coarsening and aggregation-recrystallization processes, allowing control over the average nanoparticle size.
authors.affiliation: Departamento de Física Aplicada, CINVESTAV-I. P. N., Mérida, Yucatán, 97310, México.
authors.forename: D
authors.initials: D
authors.lastname: Reyes-Coronado
authors.affiliation: Departamento de Física Aplicada, CINVESTAV-I. P. N., Mérida, Yucatán, 97310, México.
authors.forename: G
authors.initials: G
authors.lastname: Rodríguez-Gattorno
authors.affiliation: Departamento de Tecnología de Materiales, Instituto Nacional de Investigaciones Nucleares (ININ), Ocoyoacac, México. 52750, México.
authors.forename: M E
authors.initials: ME
authors.lastname: Espinosa-Pesqueira
authors.affiliation: Departamento de Física Aplicada, CINVESTAV-I. P. N., Mérida, Yucatán, 97310, México.
authors.forename: C
authors.initials: C
authors.lastname: Cab
authors.affiliation: Departamento de Física Aplicada, CINVESTAV-I. P. N., Mérida, Yucatán, 97310, México.
authors.forename: R
authors.initials: R
authors.lastname: de Coss
authors.affiliation: Departamento de Física Aplicada, CINVESTAV-I. P. N., Mérida, Yucatán, 97310, México.
authors.forename: G
authors.initials: G
authors.lastname: Oskam