For TiO2 photocatalysts, recombination of photoexcited electrons and holes would occur in crystalline defects such as oxygen vacancies, Ti ions, and surface states. Therefore, it is believed that the density of crystalline defects should be decreased to improve the photocatalytic activity of TiO2 particles. Contrary to this common knowledge, the introduction of crystalline defects by hydrogen r...

Textural evolution in sol-gel derived nanostructured unsupported titania membranes has been studied using differential scanning calorimetry (DSC), differential thermal analysis (DTA), thermal gravimetry (TG), X-ray diffraction (XRD) and N, adsorption. The anatase-to-rutile phase transformation kinetics were studied using the Avrami model. The precursor gel had a surface area of ca. 165 m2 g-', ...

Dye-sensitized solar cell (DSSC) is a potential candidate to replace conventional silicon-based solar cells because of high efficiency, cheap cost, and lower energy consumption in comparison with silicon chip manufacture. In this report, mixed-phase (anatase and rutile nanoparticles) TiO2 photoanode was synthesized to investigate material characteristics, carriers transport, and photovoltaic pe...

Molecular dynamics simulations of titanium dioxide nanoparticles in the three commonly occurring phases (anatase, brookite, and rutile) are reported. The structural properties inferred by simulated X-ray diffraction patterns of the nanoparticles were investigated. The titanium-oxygen bond length as a function of size, phase, and temperature was determined and was found to be dependent on the co...

Titanium dioxide-based nanofibers (TiO2 nanofiber) were prepared by an electrospinning technique. The electrospun composite fibers were synthesized at different concentrations of titanium isopropoxide (25.35, 50.69, 76.05 wt%) and calcinated at different temperatures (450 oC, 650 oC and 850 oC) for 2 h. The diameters of nanofibers decreased by increas...

Anatase-to-rutile phase transformation was studied in milled and unmilled samples. Ball milling was carried out in two types of ball mills, planetary and tumbler, with a ball-to-powder ratio of 40:1 over 2-48 hours. First, the unmilled samples &#10were heated in the furnace at various temperatures for different periods of time. The results revealed that the anatase-to-rutile transformation comp...

Absorption spectra of anatase and rutile TiO2 in the 150-300 nm region before and after the deposition of Pt nanoparticles were measured. For anatase TiO2, the spectral intensity in the longer wavelength region decreased (>∼210 nm), while that in the shorter wavelength region increased (<∼210 nm). In particular, spectral band intensity in the far-ultraviolet (FUV) region (∼160 nm) was increased...

A new study on the pressure-induced phase transitions of TiO(2) has been performed using all-electron density-functional theory based computations with the projector augmented wave and the linearized augmented plane wave methods considering five experimentally observed structures. The static results yield a picture that is consistent with experiments, i.e., phase transitions with pressure are p...

The rutile TiO2 films with columnar nanostructure were prepared by combining the glancing angle deposition (GLAD) technique in magnetron sputtering system with the subsequent two-step annealing treatment. Experimental results showed that all the TiO2 films kept discrete columnar structures as the Ti films deposited by GLAD and accomplished the phase transition from Ti to rutile TiO2. Such TiO2 ...