Low-temperature preparation of titania nanorods through direct oxidation of titanium with hydrogen peroxide

Hydrogen peroxide solutions were used to oxidize metallic titanium at 3 53 K for 72 h to prepare crystalline titania nanorods. The products were verified by X-ray diffraction tests to be pure anatase or a mixture of anatase and rutile, depending mainly on the anions of F-, Cl-, and SO42- in the solutions. The low-temperature crystallization was supposed to proceed in a dissolution precipitation mechanism. The field emission scanning electron microscopy and transmission electron microscopy examinations showed that the well-crystallized nanoparticles were homogeneous nanorods. Compared to the pure anatase, a much larger length/width ratio was obtained when rutile existed in the titania. This fact suggests that rutile results from a relatively lower precipitation rate, which favors also the formation of elongated particles. The absence of the strongest peak corresponding to anatase in the Raman spectra revealed that the present low-temperature prepared crystalline titania nanorods were deficient in oxygen. (C) 2004 Elsevier B.V. All rights reserved.