Papers by Keyword: Titania

Abstract: This study reviewed the synthesis of Titania with different shapes in the presence of cetyltrimethylammonium chloride (CTAC) as the famous stabilizer for directly altering the morphology and dimensions. These CTAC stabilizers usually provide the synthesis of Titania with a narrow size distribution and mostly single-crystalline structures in high yields. Many papers on the synthesis of Titania are available. However, only a few articles focus on the synthesis of Titania using CTAC as the stabilizer. The general rule for the shape transformation of Titania by CTAC stabilizer can be easily summarized based on the literature during the last ten year from https://www.sciencedirect.com/ as the data source.

Abstract: Preparation conditions of titanium oxide (TiO₂) powders were examined by the hydrolysis of titanium potassium oxalate (K₂TiO(C₂O₄)₂), through the homogeneous precipitation method (80oC for 24 h) and hydrothermal treatment (160 or 170oC for 1 h). According to the Rietveld analysis, almost a single phase of anatase TiO₂ could be obtained by the hydrothermal treatment at 160oC for 1 h, followed by the heating at 900oC for 10 min in air. The molar ratio of anatase to rutile TiO₂ was found to be controlled by optimizing the hydrothermal conditions in the solution and the heating conditions in air for the photocatalytic activity.

Abstract: Titania (TiO₂) is an important material having found its use in many technological applications. Due to its large surface-to-volume ratio, TiO₂ nanofibers (NFs) are drawing increased attention in 3^rd generation photovoltaics. The electro-optical response of TiO₂ can be tuned by metal doping and structural control at the nano level. In this research, NFs of copper (Cu) doped Titania (TiO₂) were fabricated by using electrospinning. To do away with Polyvinylpyrrolidone (PVP), the NFs were calcined and annealed in air at 500°C for 2 hours. The Energy-Dispersive X-ray Spectroscopy (EDS) results confirmed the doping of copper inside the titania after calcination. Scanning Electron Microscopy (SEM) results show NFs of varying diameters mostly in the 80 nm to 200 nm regime. SEM of the post-annealed samples shows relatively rougher fibers of reduced size compared to the uncalcined samples. The increase in roughness and reduction in the NFs diameter means an increase in the overall surface area and more efficient charge transport as Hall effect measurement results depicted that after doping of copper in nanofibers, the conductivity improved by 2 times as compared to undoped nanofibers of titania. Moreover, Ultraviolet-visible Spectroscopy (UV-Vis) showed Cu doping shifted the absorption of the spectrum.

Abstract: Several attempts have been conducted to improve the mechanical properties of mineral trioxide aggregate (MTA), including the addition of various nanoparticle materials such as silver and titania. The smaller the added material, the higher the material’s ability to fill the cavity of MTA, thus increasing the tensile strength of MTA after hydration. In this study, the effect of silver nanoparticles (AgNP) concentration and titania (TiO2) mass variation on the tensile strength of MTA was investigated. The ratio of MTA mass to AgNP volume used was 1 g to 330 μL, while TiO2 was added to MTA powder in a solid-solid state with a mass variation. The results show that the addition of AgNP and TiO2 to MTA powder can significantly increase the tensile strength of MTA from 0.404±0.125 to 1.044±0.021 and 1.378±0.391 MPa for 1.5% Ag and 0.5% TiO2, respectively.

Abstract: Titanium dioxide (TiO₂) has been exploited extensively as it shows remarkable performance in photocatalytic applications. TiO₂ thin films can be deposited onto window glass which is workable for self-cleaning applications. In this article, we have studied the role of substrate temperature for spray pyrolysis (SP) of TiO₂ thin films for studying self-cleaning applications. For thin film deposition, TiO₂ sol is prepared by the sol-gel synthesis technique. The samples are deposited at room temperature and 250 °C, respectively. The samples are characterized via Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and UV-Vis spectroscopy to determine the morphology, surface roughness, and optical properties of the thin films. SEM and AFM results show that samples deposited at 250 °C (pre-heated samples) have uniform size distribution, and defined grain boundaries, respectively. The results also show that the pre-heated sample is highly transparent in the visible region of the solar spectrum when analyzed by the steady-state UV-Vis spectrophotometer. The wettability of the prepared thin films is measured, and the results show that the pre-heated sample shows a hydrophilic character. The self-cleaning property of prepared thin films is evaluated by the photodegradation of Rhodamine B dye. It is observed that the pre-heated substrates show better photoactivity in presence of UV light irradiation. Hence, due to their hydrophilic nature and better photoactivity, these pre-heated thin films deposited by spray pyrolysis can be employed as efficient coatings for self-cleaning glass applications.

Abstract: Amorphous silica can be synthesized with controlled dimensions and morphologies by the Vapor-phase Axial Deposition (VAD) method, so we performed an exploratory study for verifying the possibility of using this technique for the obtention of a sponge-shaped ramified nanostructure with high superficial area. We were successful in synthesizing SiO₂ and SiO₂-TiO₂ with this desired morphology and characterized the materials by Scanning Electron Microscopy and X-Ray Diffraction. The obtained ceramics present pores of adequate dimensions for the use as microfiltration devices and proved to be capable of adsorbing important commercial dyes. These materials show physical characteristics that make them promising for applications on liquid and gas separations, and as very selective photocatalysts for chemical reactions and for waste and water treatment.

Abstract: Titania pillared clay membranes exhibit unique charge characteristics which are dependent on the solution pH. Doping of such membranes with precious metal like Pt induces a positive charge on the surface of the membranes, thus increasing its resistance against fouling. X-ray Diffraction (XRD) and Fourier Transform Infra-Red Spectroscopy (FT-IR) confirm the complete intercalation of anatase titania in the interlayer spaces of Montmorillonite in the present work. These membranes efficiently removed 83% of the dye from the real textile effluent in a one filtration cycle.

Abstract: Microwave-assisted hydrothermal synthesis of TiO₂ nanofibers under various temperature and pressure conditions were done in this research. High quality TiO₂ nanofiber coatings where obtained when temperature was in range 240 – 245 °C and pressure was 27.3 – 29.1 bar. Obtained TiO₂ nanofiber coatings are with a specific surface area of ​​151.5 to 158.9 m²· g^-1 before calcination. Comparing with nanopowder photocatalysts nanofiber coatings photocatalysts can be much easier removed from solution after the photocatalysis process. Such coatings with relative large specific surface area are with higher potential application in industry.

Abstract: The energy materials such as titania (TiO₂) and alumina (Al₂O₃) are the environmental friendly materials. In this paper the nanostructure of high surface area titania and alumina are fabricated by anodization process and assistance in electrochemical mold. In general, academic or research institutes can simply control the required experimental conditions in a small sample; however, it’s difficult to control the stable parameters in a large surface and a large number of nanostructural products in the industry production. In order to solve the problems of unstable current density and temperature we have designed a cooling functional electrochemical mold which can improve the nanostructural quality of energy materials during a large number production. The electrochemical mold is used for a local surface treatment at an isothermal temperature controlling. The mold limits sample for a specific treated area and current density in the electrolyte. The mold can be used for the assistance of electrolysis, electro-polishing, electro-deposition, anodization, etching, chemical deposition, pickling, and caustic processes. The mold structure includes fixture group, water-cooling electrode group, and electrode conductive group.

Abstract: In order to improve TiO₂ photocatalytic activity ZnFe₂O₄/TiO₂ nanocomposites with different ZnFe₂O₄ mass loading were produced. Obtained ZnFe₂O₄ nanoparticles were coupled with TiO₂ via microwave-assisted hydrothermal method in order to improve photon absorption in a range of visible light. Prepared nanostructures were characterized with scanning electron microscopy and X-ray diffraction. Photocatalytic activity of prepared samples was investigated by degradation of methylene blue under different light sources – LED, Hg and Osram Vitalux lamps. ZnFe₂O₄ consists of spherical nanoparticles with average size of 15 nm. TiO₂ spherical nanoparticles size is in a range of 30÷45 nm. The results show that doping TiO₂ with ZnFe₂O₄ nanoparticles increases photocatalytic activity. Photocatalytic activity increases as mass loading of ZnFe₂O₄ decreases.