Fabrication, characterization and Raman study of anatase-TiO₂ nanorods by a heating-sol-gel template process

Densely assembled TiO₂ nanorods with a diameter of 150-200nm and a length of several micrometers have been synthesized by a heating-sol-gel template process. The obtained nanorods were characterized to be single anatase-phase by X-ray diffraction. Transmission electron microscopy image revealed that the nanorods were the aggregate of many nanocrystallites with ∼10nm in diameter and indistinct polygonal shape. Selected-area electron diffraction and energy dispersive X-ray spectroscopy results confirmed that the obtained nanorods were anatase-phase with good compositional uniformity and fine crystallinity in the entire length. In addition to the fundamental phonon modes, a weak overtone scattering (B_1g) at 801cm^-1 was found in Raman scattering study which is usually observed in nano-sized materials. A new process named heating-sol-gel template process for fabrication oxide nanorods with large quantity, good compositional uniformity and fine crystallinity based on a template method was proposed and the above characterization results support the new process is a desirable process.