Papers by Keyword: Titanium Oxide

Abstract: In this study, the properties of re-melted soda-lime silicate glass cullet doped with TiO₂ were investigated in order to study the potentials to use as parent glass for glass-ceramics. TiO₂ of 0.5, 1 and 3 mol% was doped into the 71SiO₂-10Na₂O-6K₂O-5CaO-4MgO-2SrO-TiO₂-Al₂O₃ glass cullet and melted at 1500°C for 3 hours, and then annealed at 550 °C. The optical and physical properties were examined. It was found that the refractive index and density of glasses were raised with increasing of TiO₂ concentration. The optical properties measured by UV-Vis spectrophotometer showed that the UV edge in the absorption spectra was shifted to a higher wavelength, and the transmission at 583 nm was decreased. The CIE L*a*b* color measurement showed that the glasses were slightly colorless but the appearance of yellow increased with higher TiO₂ concentration. Lower thermal expansion coefficient and higher glass transition temperature as well as the dilatometric softening point were observed as the concentration of TiO₂ was increasing. Finally, the calculated activation energy was 476, 493, 506 and 637 kJ/mol with 0, 0.5, 1 and 3 mol% doped TiO₂, respectively. At doped TiO₂ of 3 mol%, the properties of glass were changed rapidly due to the substitution of [Ti⁴⁺] in local [Si⁴⁺] resulting in increasing the bond strength in glass structure.

Abstract: The objective of this research work was to study the thermal efficiency of intumescent fire retardant coating (IFRC) designed to protect structural steel in event of fire. IFRC has been effectively developed by using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL), boric acid (BA), titanium oxide (TiO₂), and bisphenol A BE-188 with polyamide amine H-2310 as curing agent. Six formulations were developed using different weight percentage (wt. %) of TiO₂ and samples were tested for char expansion in furnace at 500°C for 2 h. Bunsen burner test was used to investigate the thermal performance of coating and its performance was compared by using thermal margin value. FESEM was used for char morphology. Char composition was analyzed by XRD and FTIR. Results showed that the coating with 4 wt. % of TiO₂ provides better thermal insulation to the steel substrate.

Abstract: Biomophic titanium oxide with nanocrystalline was successfully synthesized using napkin template, which everybody uses. Unique biomorphic microstructures were characterized by field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and nitrogen absorption-desorption techniques. TiO₂ material was characterized by repetitious networks consisting of the fibers with diameter of 1-6μm. The results showed that the products were composed by polycrystalline TiO₂ nanoparticles with diameter of ca. 5-8 nm and the high specific surface area (81.0 m²·g^-1) of sample,which were believed to result from the X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and the Brunauer-Emmett-Teller (BET) method. While the concentration of acid black solution was 20 mg/L, catalyst amount 0.1 g/L, the reaction had a higher photocatalytic performance following irradiation with a visible light by xenon lamp, the decoloring rate can reach over 100% after 250 min.

Abstract: Synthesis of nanoscale TiO₂ exhibiting specific properties of electron or ion conductivity is critical to improve the performance of dye solar cells (DSC). This paper presents the modified polyol-mediated synthesis of doped TiO₂ nanoparticles. TiO₂ samples were doped with cobalt (Co) and nickel (Ni) and the effects of calcination temperature (550 °C and 650 °C) on the crystallinity of pure samples were investigated. X-ray diffraction (XRD) analysis was used to determine the effect of dopant in lattice structure. The morphology and Crystal structure of TiO₂ samples and their chemical analysis was conducted using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectrometer respectively. Results show agglomeration of spherical particles in all doped samples. Crystal structure in the doped samples reveals modified phases and major crystal phase identical to anatase. It is observed that the molar ratio of water to metal can control the nucleation and growth and prevents significant agglomeration of nanoparticles. More effective doping was recorded for samples with 0.5 % concentration. Effective hydroxyl group is detected in both 0.5% Ni and Co promising good photocatalytic material. SEM images of 0.2% Ni-doped sample shows smallest average particle size.

Abstract: TiO_x thin films were deposited by RF magnetron sputtering with TiO_x (x<2) target at varied substrate temperatures. The composition and microstructure of the films was characterized by grazing incidence X-ray diffraction, scanning electron microscopy and Raman spectroscopy, which revealed that the films deposited at low temperatures were amorphous, and as the temperature increased up to 600 °C, the prepared films became crystalline and a TiO₂ anatase phase was identified. Also the electrical resistivity of the as-prepared TiO_x films was investigated as a function of the deposition temperature. The result indicates that with the raise of substrate temperature, the electrical resistivity of the deposited films decreased sharply.

Abstract: In this work, a magnetic polymer electrolyte composed by agarose as polymer matrix, NMP as solvent and NiO/TiO₂ mixed nanoparticles as modifier was investigated and employed in the solid-sate dye-sensitized solar cells (DSSCs). The influence of NiO/TiO₂ mixed nanoparticles on the morphology and ionic conductivity of the polymer electrolyte was studied by SEM and electrochemical impedance spectra. From SEM analysis, the mixing of NiO with TiO₂ nanoparticle in polymer electrolyte leads to smooth surface of the polymer electrolyte films. The polymer electrolyte modified by mixed nanoparticles with NiO: TiO₂ ratio of 1:4 shows the maximum ionic conductivity of 6.64×10^-3 S·cm^-1. From photovoltaic performance study, the increase of NiO: TiO₂ ratio in polymer electrolyte leads to an improvement in light-to-electric conversion efficiency. The optimal photoelectric efficiency is achieved at NiO: TiO₂ ratio of 1: 4. Besides, after treatment under an external magnetic field, the DSSC modified with NiO: TiO₂ ratio of 1: 4 exhibits a better photovoltaic performance than that of DSSC without magnetic field treatment.

Abstract: Atomic layer deposition (ALD) is a precision growth technique that is able to deposit either amorphous or epitaxial layer on a wide range of substrates. Multilayer thin films have been widely studied because their properties are different from those of bulk materials constituents owing to the two-dimensional films and high density of interfaces. Multilayer nanostructured thin films were fabricated on silicon and glass substrates by ALD. The optical and electrical of multilayer ZnO/TiO₂/ZnO films were investigated. The microstructure compositions and surface morphology of these multilayer films were analyzed by X-ray diffraction (XRD), Atomic force microscope (AFM) and Scanning electron microscope (SEM). The optical properties were characterized using photoluminescence (PL) and UV-VIS spectroscopy. XRD patterns confirmed that ZnO with wutrtize crystal structure and TiO₂ with anatase structure were presented. The degree of crystallinity of multilayer thin films has been improved through the deposition of ZnO. The intensity of UV luminescence of the multilayer has increased as compared to the single layer TiO₂ and bilayer ZnO/TiO₂. The multilayer ZnO/TiO₂/ZnO has high transmittance (above 80%) in visible region. All the result suggested that the use of multilayer thin films effectively enhanced the quality of films crystallinity and optical properties as compared to single layer ZnO and bilayer ZnO/TiO₂.

Abstract: Anodic oxidation processing titanium foil in an aqueous solution of hydrofluoric acid+ glacial acetic acid+polyethylene glycol constant pressure, Synthesized by high-density ordered TiO₂ nanotube arrays. Calculate the degradation rate of chloramine phosphorus, TiO₂ nanotubes catalytic performance test.The use of scanning electron microscopy (SEM) and X-ray diffraction (XRD) to characterize the morphology and structure of the nanotubes, Visits oxidation time on the morphology and size of the nanotube arrays, mapping and analysis of current - time curve. An average particle diameter d of the sample may be calculated the strongest diffraction peak of the plane FWHM ,So chloramine phosphorus selection of organic phosphorus drugs for the photocatalytic degradation object, Molybdenum blue spectrophotometry measured and calculated degradation rate, Study of heat treatment temperature and anodizing time photocatalytic degradation, And the sol - gel prepared TiO2 thin film and photocatalytic comparative experiments.

Abstract: TiO₂ nanotube arrays were fabricated through anodization in the glycol electrolyte system. The new composite structures of the bottom nanotube and the upper nanowire with a length of 15 um to 20 um were prepared. The influence of the water contents in the electrolyte with respect to the composite structure was studied through two-step anodization. The results show that the composite structure can be obtained based on the moderate etching rate of the electrolyte and the selective etching of the nanotube when the glycol system electrolyte contains 0.4wt% NH₄F and 2 vol% H₂O.

Abstract: We evaluated the surface area, pore size distribution, and electrical characteristics of titanium oxide films formed under different sintering and cleaning conditions. In addition, we examined the microstructure of the titanium oxide films by forming cross-sectional surfaces. The necking structure of the titanium oxide films strongly influenced the conversion efficiency of the dye-sensitized solar cell. And, the conversion efficiency was improved by the increasing firing temperature and treating with TiCl₄ and ozone water.