We have studied metalorganic chemical vapor deposition of TiO2 thin films using titanium tetra-isopropoxide [TTIP, Ti(O–C3H7)4] and NH3 as a catalyst at deposition temperatures ranging from 250 to 365◦C. At deposition temperatures above 330◦C, pyrolytic self-decomposition of TTIP is dominant regardless of the use of NH3, and the activation energy for TiO2 film formation is 152 kJ/mol. At deposi...

Unique nanorod-like mesocrystals constructed from ultrathin rutile TiO2 nanowires were successfully fabricated for the first time using a low-temperature additive-free synthetic route, and the mesocrystal formation requirements and mechanism in the absence of polymer additives were discussed. The ultrathin nanowires were highly crystalline and their diameters were found to be ca. 3–5 nm. The ru...

Titania is the most widely studied photocatalyst. In its mixed-phase configuration ( anatase–rutile form) – as manifested in the commercially available P25 Degussa material – titania was previously found to exhibit the best photocatalytic properties reported for the pure system. A great deal of published research by various workers in the field has not fully explained the underlying mechanism f...

Rutile-phase TiO2 nanotube arrays without broken walls were formed by annealing of anodically formed nanotubes in a propane flame at 650 °C and in air at 750 °C. An unusual morphological transformation was observed from the ellipsoidal pore-shapes of titania nanotubes grown in aqueous electrolyte to a square-shaped pore structure subsequent to the anneals. 750 °C annealed nanotubes were found t...

Nitrogen-doped, porous rutile has been prepared by hydrothermal reaction of TiN in nitric acid, with the nitrogen atoms present in the interstitial sites and in the form of adsorbed nitrate ions. The N-rutile powder exhibits outstanding photocatalytic activity toward degradation of adsorbed methylene blue under visible light irradiation.

Mixed-phase TiO2 nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM), and X-ray diffraction (XRD). The topo...

Discovering new materials with tailored chemical properties is vital for advancing key technologies in catalysis and energy conversion. One strategy is the modification of a material's crystal structure, and new methods allow for the synthesis and stabilization of potential materials in a range of crystal polymorph structures. We assess the potential reactivity of four metastable oxide polymorp...

The temperature dependence of the pre-edge features in x-ray absorption spectroscopy is reviewed. Then, the temperature dependence of the pre-edge structure at the K-edge of titanium in rutile TiO(2) is measured at low and room temperature. The first two peaks grow with temperature. The fact that these two peaks also correspond to electric quadrupole transitions is explained by a recently propo...