The Effect Of Heat Treatment On Phase Transformation And Morphology Of Nano- Crystalline Titanium Dioxide (Tio 2 (original) (raw)
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Materials, 2018
Titanium biomaterials’ response has been recognized to be affected by particles size, crystal structure, and surface properties. Chemical and structural properties of these nanoparticle materials are important, but their size is the key aspect. The aim of this study is the synthesis of TiO2 nanoparticles by the sol-gel method, which is an ideal technique to prepare nanomaterials at low temperature. The heat treatment can affect the structure of the final product and consequently its biological properties. For this reason, the chemical structure of the TiO2 nanoparticles synthesized was investigated after each heat treatment, in order to evaluate the presence of different phases formed among the nanoparticles. FTIR spectroscopy and XRD have been used to evaluate the different structures. The results of these analyses suggest that an increase of the calcination temperature induces the formation of mixed-crystalline-phases with different content of anatase and rutile phases. The result...
Nanocrystals of Titanium dioxide were prepared via sol-gel and solvothermal method. They were characterized by X-ray diffraction and Scanning Electron Microscopy studies. The anatase and rutile phase reflections of the Titanium dioxide nanocrystals were identified by X-ray diffraction data. The micro strain value of the nanocrystals were analysed by W-H plot method. Very small value of micro strain was observed in all the samples. The sample ST-600 shows zero micro strain. The morphology shows increase of size due to agglomeration at higher calcination temperatures. Key Words: Titanium dioxide, Anatase, Rutile, W-H plot, Micro strain
DSC investigation of nanocrystalline TiO 2 powder
Journal of Thermal Analysis and Calorimetry, 2011
The aim of the article is to investigate the influence of particle size on titanium dioxide phase transformations. Nanocrystalline titanium dioxide powder was obtained through a hydrothermal procedure in an aqueous media at high pressure (in the range 25–100 atm) and low temperature (≤200 °C). The as-prepared samples were characterized with respect to their composition by ICP (inductive coupled plasma), structure and morphology by XRD (X-ray diffraction), and TEM (transmission electron microscopy), thermal behavior by TG (thermogravimetry) coupled with DSC (differential scanning calorimetry). Thermal behavior of nanostructured TiO2 was compared with three commercial TiO2 samples. The sequence of brookite–anatase–rutile phase transformation in TiO2 samples was investigated. The heat capacity of anatase and rutile in a large temperature range are reported.
Journal of Physics: Conference Series
Globally, the use of titanium dioxide (TiO2) for photocatalytic activities has a tremendous attention because of the numerous advantages which can be obtain from photocatalysts. The usage of TiO2 was verified to be nontoxic, biologically inert, physically and chemically stable against corrosion. The TiO2 photocatalyst was prepared via a simple precipitation method using titanium tetrachloride (TiCl4) in the presence of ammonium sulfate was used to obtain samples of mesoporous titanium dioxide with anatase structure. In the work discussed in this paper, titanium dioxide (TiO2) nanoparticles were synthesized by wet precipitation method under different conditions. Prepared TiO2 powders were characterized by XRD, FESEM and UV Vis-DRS. Different conditions, for example reflux time (2 and 4 hours) and calcination temperature (350ºC), were changed to achieve to best nanocrystallite material. It was found that variation of all these conditions could strongly affect crystallinity, morphology, and crystallite size. The crystallite sizes of nanoparticles, calculated by using the Scherrer equation, were from approximately 11 to 15 nm.
Synthesis and Characterization of TiO2 Nanoparticles
The ever increasing interest in Titanium Oxide (TiO2, Titania) is motivated by its applications in solar cells, biomaterials, photo catalytic activities. Nano crystalline titania is preferred in these applications due to chemical stability, mechanical hardness, high refractive index, excellent transmission in visible region. Titania exists in three different crystallographic phases i.e. anatase, rutile and brookite. Anatase and rutile crystallises in tetragonal phase where as brookite has orthorhombic phase. Titania nanoparticles were synthesized via sol-gel method using TiCl4 precursor. In sol-gel method ammonia was used as the gelation agent. The titania nanoparticles were then centrifuged. In order to study the effect of pH on titania nanoparticles different nanoparticles were prepared by varying the pH of the sol. As-synthesized samples were also annealed at different temperature (upto 500°C). XRD results show the formation of highly crystalline titania nanoparticles. It was found that below 400°C anatase phase dominates while annealing at high temperature results in conversion of anatase to rutile phase. With increase in annealing temperature the peak intensities corresponding to rutile phase increases. Variation in sizes of nanoparticles from 20 nm to 500 nm is observed with variation in annealing temperature and pH. Titania nanoparticles prepared in this research work were homogenous and good interconnection was formed between the particles indicating the good mechanical strength of sol-gel prepared nanoparticles.
Synthesis of nanocrystalline TiO 2 at 100 °C
Materials Letters, 2004
A simple gel to crystal conversion route has been followed for the preparation of TiO 2 at 80 -100 jC under refluxing conditions. Freshly prepared titanium hydroxide gel is allowed to crystallize under refluxing and stirring conditions for 6 -12 h. Formation of nanocrystallites of anatase is confirmed by X-ray diffraction (XRD) study. The anatase phase converts into rutile when calcined at 700 jC for 12 h. Raman scattering experiments were also performed to confirm both anatase and rutile phases. Transmission electron microscope (TEM) investigations revealed that the average particle size is 10 nm for the anatase phase whereas it is 35 nm for the rutile polymorph. D
Nanocrystalline TiO2 by three different synthetic approaches: A comparison
Bulletin of Materials Science, 2007
A comparison of the efficiency of three different synthetic routes viz. sol-gel method involving templating, mechanochemical synthesis and combustion synthesis for the production of nanostructured TiO 2 , is reported. In the sol-gel method, nanocrystalline TiO 2 is produced when titanium tetraisopropoxide is templated onto dodecylamine which forms the liquid crystalline hexagonal structure and the template is then extracted using 1 : 1 solution of ethanol-hydrochloric acid mixture. Mechanochemical synthesis of nanocrystalline TiO 2 involved mechanical milling of stoichiometric amounts of titanium and cupric oxide in a planetary ball mill using stainless steel vial with wear resistant stainless steel balls. Nanocrystalline TiO 2 is produced by the combustion reaction involving titanyl nitrate and fuels like glycine and citric acid. Nanostructured TiO 2 with an average particle size of ~ 14 nm is produced by the sol-gel method whereas the mechanochemical reaction between titanium and cupric oxide resulted in the formation of nanocrystalline TiO 2 with an average particle size of ~ 20 nm after 12 h of milling. On the other hand, combustion synthesis resulted in the formation of nanocrystalline TiO 2 with an average particle size of less than ~ 50 nm. The microstructures of nanocrystalline TiO 2 produced by the above three methods are analysed.
In the current work, the morphology, structure, and optical properties of TiO 2 nanoparticles were studied to examine the effect of hydrothermal temperatures treatment on the nanoparticle's properties. The prepared TiO 2 nanoparticles were analyzed by X-ray diffraction (XRD), high-resolution electron microscopy (HR-TEM), Fourier-transforming infrared spectroscopy (FTIR), and Ultraviolet-Visible (UV-Vis) spectrophotometers. Hydrothermal treatment leads to a crystalline transition from the anatase phase to the monoclinic phase in the commercial nanoparticles of TiO 2 and decreases the particle size. Results from the HR-TEM indicated that a nanosheet was observed in comparison to commercial TiO 2 nanoparticles after hydrothermal treatment. Analysis of UV-Vis revealed that the transmission and absorption of TiO 2 samples treated with different hydrothermal reaction temperatures were changed compared to the original sample. Taken together, hydrothermal temperature treatment signifies the morphology, structure, and optical properties of TiO 2 .
Room temperature synthesis of highly crystalline TiO2 nanoparticles
Materials Letters, 2013
Hydrolysis of titanium isopropoxide alcoholic solution has been used to prepare the crystallized TiO 2 nanoparticles at low temperature. Concentration ratio was used to control the pathway of sol-gel process and change the physical characteristics of TiO 2 nanopowders. The crystallinity, morphology and size of aged TiO 2 nanopowders were studied by X-ray diffraction and Scanning Electron Microscopy (SEM). FTIR and, Thermo-Gravimetric (TG) analysis were used to identify the functional groups and thermal behavior of prepared samples. Experimental results have shown that high crystalline TiO 2 nanomaterial with anatase polymorph can be obtained at room temperature. It has been found that the crystallinity of synthesized TiO 2 nanoparticles is two times higher than the highest crystalline sample obtained by our last novel method .
Nano particles of Titanium dioxide are prepared by using a sol-gel route by using hydrolysis of Titanium tetraisopropoxide with ethanol and water mixture as titania source. After heat treatment of the samples, we characterized their structures and basic properties by using conventional XRD, FT- IR, scanning electron microscopy (SEM), UV-Vis spectroscopy and photoluminescence spectroscopy (PL). The X-ray diffraction pattern revealed that the calcined sample of TiO2 has both anatase and rutile phases. The spherical shape or spheroidal shape was observed using scanning electron microscopy. The rate of recombination and transfer behavior of the photo excited electron-hole pairs in the semiconductors was recorded by photoluminescence. It was found that annealing could improve the crystallization of TiO2 powders and accelerated the phase transformation from anatase to rutile. The result shows that the different calcination time and calcination temperature, have a lot of influences upon the properties of nano TiO2.