Direct Formation of Crystalline Phase Pure Rutile TiO2 Nanostructures by a Facile Hydrothermal Method

Small titania, TiO 2, nanoparticles (< ∼10 nm) are normally restricted to the anatase polymorph, and synthesis of stable rutile nanoparticles below the critical size is challenging. Here, we report on a fast, low temperature and environmentally benign hydrothermal method to prepare phase pure rutile TiO 2 nanorods with an average diameter of 42 nm covered by crystalline spherical nanoparticles around 10 nm in size. The synthesis approach utilizes titanium tetraisopropoxide and glycolic acid at 200 °C for 3–12 h, and the samples were characterized by powder X-ray diffraction (PXRD), UV–vis spectroscopy, FT-IR spectroscopy, and transmission electron microscopy (TEM). In addition, in situ synchrotron PXRD measurements were carried out to follow the formation and growth of the rutile nanoparticles under the present mild hydrothermal conditions, and it is observed that rutile TiO 2 is formed directly from solution without intermediate brookite or anatase phases.