Papers by Keyword: TiO₂ Nanofibers

Abstract: Ag/TiO₂ nanofibers were obtained by sol-gel method combined with uniaxial electrospinning. The effects of different sintering temperatures (400°C, 500°C, 600°C) and different concentrations of silver (0 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%) on photocatalytic activity of TiO₂ were investigated. The morphology and interface interaction of the Ag/TiO₂ composites were investigated by SEM, TEM, XRD and UV-visible spectrophotometer. The experimental results showed that the diameter of the fiber sintered at 400°C is about 120 nm and the fiber is composed of 10-20 nm small particles. The degradation rate of methylene blue was 71% for the Ag/TiO₂ composites fiber with 1.0wt% silver and sintered at 400°C.

Abstract: In the present work formation of macro-size TiO₂ nanofiber layers in microwave synthesis were studied. Anatase nanopowder and 10M KOH solution were used as raw materials. Microwave assisted synthesis method permitted to obtain TiO₂ nanofibres containing individual nanowires with a diameter of 5nm and a specific surface area up to 129m²/g. Macro size layer of TiO₂ nanofibers was obtained on the surface of microwave vessel. Total surface area covered with TiO₂ was about 390cm². Modification with platinum allows to increase photocatalytical activity of TiO₂ macro size fiber layer up to 94.4% in UV irradiation and up to 11.6% under visible light irradiation.

Abstract: In situ TiO₂ nanofiber arrays have been successfully produced directly on a Ti-6Al-4V substrate by using thermal oxidation under a limited supply of oxygen. Their morphology, elemental composition, crystal structure, surface roughness and surface wettability were characterized by field-emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffractometer (XRD), atomic force microscope (AFM) and contact angle goniometer, respectively. The results of material characterization studies revealed that TiO₂ nanofibers possessed greater surface roughness and wettability, as well as the degree of crystallinity. In vitro characterization have also been evaluated by using bovine articular chondrocytes on the resulting TiO₂ nanofibrous surface at different time points. Cell adhesion was observed qualitatively by using FESEM and cell proliferation was determined quantitatively by using AlamarBlue reduction assay. The results showed that the TiO₂ nanofibrous substrate triggers enhanced chondrocytes adhesion, proliferation, and production of extracellular matrix (ECM) fibrils compared to untreated substrate. These results suggest that the oxidation process produces a surface structure to which chondrocytes affinity, and thus this surface would has potential use in implants designed for cartilaginous applications.

Abstract: In this paper, a kind of fibrous TiO₂ has been prepared through hydrothermal synthesis and a paper fabricated from the fibrous TiO₂ has been obtained. The composition, morphology, and size of the fibrous TiO₂ were characterized by using X-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. And the morphology of the paper was characterized by polarizing microscope. The thickness, softness, and writing properties of the paper were detected by a vernier caliper and a pen. The results indicate that the diameter of the fibrous TiO₂ is ~ 200 nm, the thickness of the fabricated paper is ~ 0.35 mm, and the paper can be tolerated writing by a UM-100 ball pen. The excellent properties of the prepared paper may change the applications of fibrous TiO₂ in papermaking industry.

Abstract: The cobalt-based FT catalysts, in which Co crystals supported on TiO₂ nanofibers, were prepared by convenient method. The structure of the catalysts was examined and cobalt-based catalysts using TiO₂ nanofibers as a support for the application of FT were investigated. Based on CO hydrogenation, the cobalt species dispersed on the TiO₂ nanofibers have higher selectivity and activity.

Abstract: Titanium dioxide nanofibers were fabricated by electrospinning technique. The titania solutions were obtained from adding various types of Ti precursor (Ti(OBu)4, Ti(OiPr)4, and Ti(OPr)4) to an ethanol solution containing polyvinyl pyrrolidone (PVP). Acetic acid was used to stabilize the solution and to control the hydrolysis reaction. The porous and well-defined crystalline structure was obtained after calcined at 450oC for 1 h. The thermal behavior, phase composition including crystallite size, as well as the morphology of as-synthesized nanofibers was obtained from thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The average diameter of these nanofibers was in the range from 100 to 400 nm depending on titania precursor. The photocatalytic activity of TiO2 fibers were evaluated for NOx degradation in a gaseous phase. The results demonstrated that at the same catalyst loading, the photocatalytic activity of TiO2 nanofiber was higher than the commercial Degussa P-25.