Temperature effects during Ostwald ripening on structural and bandgap properties of TiO2 nanoparticles prepared by sonochemical synthesis
Por:
González-Reyes L., Hernández-Pérez I., Arceo, LDB, Dorantes-Rosales H., Arce-Estrada E., Suárez-Parra R., Cruz-Rivera J.J.
Publicada:
15 nov 2010
Resumen:
Anatase TiO2 nanocrystalline (6 nm) with BET specific surface area of 300 m(2)/g and direct bandgap of 3 31 eV were prepared sonochemically and then it was subjected to thermal treatment from 400 to 900 degrees C for 2 h, in order to produce variable anatase-rutile ratio Three stages were considered in the samples thermally treated (i) anatase grains coarsening as a result of heat treatment temperature increasing the structural homogeneity and crystallinity and both phenomena produce a reduction in the specific surface area, (ii) coexistence of two phases (anatase and ruffle) separated by a transition region, called an interface, and (iii) process where the rutile grains evolve Into a new equilibrium shape without the presence of anatase phase, minimizing the total surface and the grain boundary energies, by mass transport diffusion. In this last stage the rutile phase has the sole function of growth and densification. The structure evolution, morphology and microstructure characterist
Filiaciones:
Univ Nacl Autonoma Mexico, Ctr Invest Energia, Temixco 62580, Morelos, Mexico
Instituto de Ciencia y Tecnología del Distrito Federal, ICyTDF, República de Chile 6, Centro 06010, México D.F., Mexico
Universidad Autónoma Metropolitana-A, Departamento de Ciencias Básicas, Av. Sn. Pablo No. 180, México 02200 D.F., Mexico
Instituto Politécnico Nacional, Departamento de Ingeniería Metalúrgica y Materiales, ESIQIE-UPALM, México 07738 D.F., Mexico
Instituto de Metalurgia-Facultad de Ingeniería, UASLP, San Luis Potosí, Mexico
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