Synthesis of TiO 2 Nanowires via Hydrothermal Method (original) (raw)
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Effect of alkali strength on the hydrothermal growth of photoactive TiO2 nanowires
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Titanium dioxide nanowires have been prepared by the alkali hydrothermal treatment of TiO2 nanoparticles in presence of different hydroxides and characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive x-ray (EDX), N2 adsorption-desorption measurements, powder x-ray diffraction (XRD) and UV-Vis spectroscopy. Interestingly, only the strong bases (NaOH and KOH) formed mainly anatase titanium dioxide nanowires with the evident collapse of definitive (110) rutile XRD peak. The KOH-based titanium oxide nanowires exhibited comparatively low diameter (∼5 nm), high surface area (228.34 m2/g), and low band gap energy (2.90 eV), and showed the most remarkable photocatalytic degradation (98.87 %). However, the NH4OH-based titanium dioxides were nanoparticles having insignificantly modified morphology and least photocatalytic efficiency. The effect of operating variables on the degradation of aqueous methylene blue (MB) over the obtained ...
Electrical Conductivity Characteristic of TiO2 Nanowires From Hydrothermal Method
Journal of Physics: Conference Series, 2014
One dimensional nanostructures of titanium dioxide (TiO2) were synthesized via hydrothermal method by mixing TiO2 as precursor in aqueous solution of NaOH as solvent. Then, heat and washing treatment was applied. Thus obtained wires had diameter ~15nm. TiO2 nanowires will be used as a network in solar cell such dye-sensitized solar cell in order to improve the performance of electron movement in the device. To improve the performance of electron movement, the characteristics of TiO2 nanowires have been analyses using field emission scanning electron microscopy (FESEM) analysis, x-ray diffractometer (XRD) analysis and brunauer emmett teller (BET) analysis. Finally, electrical conductivity of TiO2 nanowires was determined by measuring the resistance of the TiO2 nanowires paste on microscope glass.
Thermal evaporation growth and the luminescence property of TiO 2 nanowires
Journal of Crystal Growth, 2005
Single crystalline TiO 2 nanowires have been successfully grown on alumina substrates using a high-frequency (350 KHz) dielectric heater at 1050 1C by a two-step of thermal evaporation method without using any catalyst. The first step is to form the high surface energy TiO 2 seeds on the low surface energy alumina substrates. The second step is to grow the single crystalline TiO 2 nanowires on the alumina substrates by the vapor-solid (VS) mechanism. The field emission electron microscopy (FESEM) image showed a uniform diameter of 60-90 nm and length of hundreds of nm to 2 mm for the TiO 2 nanowires. The high-resolution transmission electron microscopy (HRTEM) image showed that the TiO 2 nanowires are of single crystalline rutile structure. The luminescence properties were investigated by cathodoluminescence (CL) in FESEM. The result is surprising in that the TiO 2 nanowires are of rutile phase, but the luminescence properties similar to the bulk TiO 2 of anatase phase. r
Synthetic precursor to vertical TiO 2 nanowires
Materials Research Express, 2014
An easy protocol for improvement in formation of the photoanode in a dye sensitized solar cell is addressed. Specifically, a novel synthesis for the formation of a TiO 2 precursor: titanium butanediolate, is detailed. This precursor is found to have higher thermal and temporal stability than commercially available TiO 2 precursors and it has successfully been employed in the one-pot synthesis of rutile nanowires grown directly on a conducting substrate: fluorine doped tin oxide (FTO). This synthesis has been further extended to directly form a mixed phase TiO 2 film consisting of rutile nanowires along with anatase spherical particles on FTO and this assembly has been used as the photoanode in a dye-sensitized solar cell. The synergistic effect of the two phases has provided a net DSSC efficiency of 4.61% with FF = 61%.
MATEC Web of Conferences, 2015
We have investigated TiO2 nanostructures prepared by anodization in conjunction with hydrothermal method using Ti metal plates. The TiO2 nanoporus were fabricated by electrochemical anodization in a NH4F/EG4/H2O electrolyte system. Ultrasonic wave was used to clean the surface of TiO2 nanoporus in the medium of water after completing the anodization. After drying in air, the nanoporusarrays were calcined at 450 °C for 2 h in air. The TiO2 nanostructures were converted by hydrothermal in air.The TiO2 nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD patterns show the TiO2 anatase structure. SEM images indicate that the TiO2 structures depend on preparation temperatures. The density of TiO2 nanostructures increases as the time increases. The growth of TiO2 nanostructures was observed to be times dependence. The nanostructures are nanowires and nanospikes when the peraring time was 18 h, nanoflowers when the preparing time was 24h. This approach provides the capability of creating patterned 1D TiO2 nanowires at 18h. The diameter of TiO2 nanowires varies from 20 nm to 25 nm and length of several 250 nm.
Journal of Materials Science: Materials in Electronics, 2014
In this work, a typical hydrothermal synthesis to grow long, high density, vertically aligned, well oriented and homogenous TiO 2 nanowires arrays and flower-like film on conductive and nonconductive (glass) sides of fluorine doped tin oxide (FTO-glass) substrate are presented. Under the same conditions, the TiO 2 nanowires arrays were directly grown on the FTO coated side. While the flower-like nanostructures were grown on the glass side. Two cleaned FTO-glass samples were placed inside the autoclave cylinder. The samples were placed at horizontal and inclined at 45°respectively. The average diameter and length of nanowires are 150 nm and 7.0 lm respectively. Also the average diameter of the prepared flowerlike nanostructure of TiO 2 is &5-10 lm. The flower-like nanostructure growth was confirmed in the absence of FTO by scratched line made on conductive side. The optical propertied of the TiO 2 flower-like nanostructures was also investigated. The synthesized products were characterized by SEM equipped with EDS, XRD and UV-VIS NIR spectrophotometer.
Hydrothermally growth of TiO2 Nanorods, characterization and annealing temperature effect
Kuwait Journal of Science
Titanium dioxide TiO2 nanorods were successfully grown on conductive glass FTO substrate using the hydrothermal method at a temperature of 160 oC. Surface topography, structure, and optical characteristics were studied according to the influence of annealing temperature (450, 550, and 650) oC. The surface topography results reveal that the TiO2 had nanorods structure with a tetragonal shape, and the rod diameter increases from 84.2 nm to 116.6 nm with increasing the annealing temperature. The crystal structure of the grown TiO2 NRs exhibits a high crystallinity of polycrystalline nature with anatase and rutile phases. The preferential orientation was along (204) plane for anatase tetragonal structure. AFM image shows an intense edge, uniform surface morphology, and increased grain diameter with annealing temperature. The optical properties of TiO2 NRs were investigated, and the absorption edge shows a blue shifting as the annealing temperature increases when considering the crystall...
Influence of Growth Temperature on TiO2 Nanostructures by Hydrothermal Synthesis
International Journal of Engineering and Advanced Technology
Titanium dioxide (TiO2) shows a great interest in solar cell application due to its morphology and crystalline structure. Moreover, it is an affordable compound that could make solar cells more economical than traditional silicon solar cells. In this study, one-step hydrothermal method is demonstrated to synthesis TiO2 nanorods/nanoflowers morphology on different hydrothermal reaction temperature. Increasing the reaction temperature could influence the formation of highly crystalline rutile phase of titania thin film. Moreover, the growth mechanism under different reaction temperatures has pronounced effects on the preferred orientation, morphologies and sizes of the structure. The results serve as guidance principle in preparing high quality solar cell specifically in heterojunction thin film fabrications.
Controlled Structure and Growth Mechanism behind Hydrothermal Growth of TiO2 Nanorods
Scientific Reports
Fabrication of uniform vertically-aligned titanium dioxide nanorods (TiO2 NRs) was achieved by hydrothermal growth on a fluorine-doped tin oxide (FTO) glass substrate. The substrate was coated by a TiO2 seed layer composed of titanium (IV) butoxide (TBO) as a precursor in an HCl solution. To reduce the amount of toxic substances used in this work, a minimal amount of HCl was used. On a larger scale, this method would require less precursor and therefore be a cost-savings. The aim of the present work is to achieve high crystalline orientations of TiO2 NRs for low quantities of both TBO precursor and HCl solutions. Results showed that the 0.7% TBO TiO2 NRs after 1.5 h of hydrothermal treatment exhibited the optimal crystalline orientation along [001] while the (002) plane is the dominant facet. The results demonstrate high transmittance of visible light and well-formed crystalline structures that offer a fast electron pathway along the length of the TiO2 NRs with less grain boundaries...
Journal of Materials Science & Technology, 2015
TiO 2 nanowire arrays were successfully fabricated by liquid-phase deposition method using porous alumina templates. The obtained TiO 2 nanowires were characterized using Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) analysis. Results of electron microscopic observations indicated that the nanowires were smooth and uniform with a diameter of about 50-80 nm and several micrometers in length. SAED, Raman, and XRD measurements showed that TiO 2 nanowires were single-crystalline with a pure rutile structure after heating at 800 °C for 10 h. In this situation, the nanowire constituents grew preferentially along the <001> direction. Furthermore, the formation process and mechanistic study of the TiO 2 nanowire arrays were proposed and discussed in detail. The nanowires are clearly produced by the deposition of TiO 2 particles on the inner wall of the template nanochannels.