No abstract

We report on a novel and facile approach for the direct growth of F-doped flower-like TiO(2) nanostructures on the surface of Ti in HF solutions under low-temperature hydrothermal conditions. The influence of the experimental parameters such as temperature, reaction duration, and the HF concentration on the morphology and photoelectrocatalytic activity of the formed F-doped flower-like TiO(2) nanostructures was systematically studied. The presence of HF and the reaction time play an important role in the formation of the F-doped flower-like TiO(2) nanostructures. The synthesized novel F-doped TiO(2) flower-like nanomaterials possess good crystallinity and exhibit high photoelectrochemical activity for water-splitting and photodegradation of organic pollutants compared with P-25, which is currently considered to be one of the best commercial TiO(2) photocatalysts. The approach described in this study provides a simple and novel method to synthesize F-doped TiO(2) nanostructured materials that are ready for practical applications such as the photodegradation of wastewater.

Carbon-doped TiO 2 micro-/nanospheres and nanotubes have been synthesized via a single source chemical vapor deposition in an inert atmosphere. Organic compound Ti(OC 4 H 9 ) 4 was used as the titanium, oxygen, and carbon source, while argon served as the carrier gas. The effect of the temperature, substrate, and the flow rate of the carrier gas is investigated. The diameter of the formed carbon-doped TiO 2 spheres can be adjusted from 100 nm to several micrometers by varying the flow rate of the carrier gas. The as-prepared TiO 2 nanotubes are highly ordered with a diameter of about 100 nm and a wall thickness of around 15 nm. The estimated optical band gap is 2.78 eV for the formed carbon-doped TiO 2 microspheres and 2.72 eV for the synthesized carbon-doped TiO 2 nanotubes, both of which are much smaller than that of bulk anatase TiO 2 (3.20 eV). The photocurrent of the carbon-doped TiO 2 spheres is much higher than that of commercial P-25, which is currently considered as one of the best TiO 2 photocatalysts, especially under visible light irradiation. The possible mechanism of the formation of TiO 2 spheres and nanotubes is also discussed.

Eu2O3 nanotubes have been successfully fabricated by an improved sol-gel template method within the nanochannels of porous anodic alumina templates. The morphology, structure, and composition of the nanotubes were characterized by means of X-ray diffraction techniques, scanning electron microscope, transmission electron microscopy, and selected-area electron diffraction. The results show that the Eu2O3 nanotubes are polycrystalline with a cubic structure. The outer diameter of nanotubes is 50-80 nm, and the thickness of the tube wall is about 5 nm. The mechanism of nanotube formation was discussed.

No abstract

Different morphological one-dimensional ZnO:Ce nanostructures were synthesized on a large scale. The microstructures and vibrational properties were investigated by x-ray diffraction, electron microscopy, Raman spectroscopy, and infrared spectroscopy. The results show that Ce can effectively control the growth of ZnO nanostructures. The change of the morphology and local structure of ZnO under the influence of Ce results in the variation of vibrational properties. In Raman spectra of doped samples, some classical modes, such as A1 and E1 modes, disappear, and two anomalous modes at 527 and 667 cm−1 are observed, whose intensity decreases with the increase of synthesis temperature. In infrared spectra, some surface phonon modes appear. Compared with those of the undoped sample, all the normal modes observed in the Ce-doped samples blueshift, and the extent of the blueshift decreases with increasing synthesis temperature in the Raman and infrared spectra.

No abstract

No abstract