C-140 DAE-BRNS 63thrd Interdisciplinary International Symposium Symposium on Materials on Materials Chemistry,December Chemistry, December 7-11,2010,Mumbai,India 6-10, 2016, Mumbai, India
Chemogenic Synthesis and Characterizations of Titanium Dioxide Nanoparticles Via Hydrothermal Route Shirajahammad M. Hunagund, Vani R Desai, Malatesh Pujar, Jagadish S. Kadadevaramath and Ashok H. Sidarai* Department of Studies in Physics, Karnatak University, Dharwad-580003, Karnataka, India. email:
[email protected]
Abstract Herein, we report the simple facial hydrothermal route for the synthesis of Titanium dioxide (TiO2) nanoparticles (NPs) using nitric acid as a capping agent. The successful formation of TiO2 NPs was confirmed by UV-vis spectroscopic measurement and the method of UV-vis diffuse reflectance spectroscopy (DLS) was invoked to estimate the band gap energy. The synthesized TiO2 NPs were characterized by various techniques such as X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Energy dispersive X-ray spectroscopy (EDS). The results obtained signify the following features; Estimated Eg value using DLS method was found to be 3.07 eV. XRD analysis confirms the phase formation and presence of nanocrystalline TiO2 and the estimated average particle size using Scherer’s equation is 50.7. TEM analyses show that NPs were of spherical shape with an average particle size of about 75 nm, The SAED patterns revealed that the diffraction ring shows brighter spots. The EDS analysis reveals the chemical compositions of the NPs having Ti and O elements.
Introduction TiO2 NPs have received considerable attention in recent years because of their unique catalytic, electronic, optical, structural properties and consequent technological applications as catalysts, sensors, nanoelectronic devices, biosensors, dye-sensitized solar cells and image contrast agents in medical diagnostics [1, 2]. Performance and applicability depend critically on their size, shape, surface morphology, composition, and fine structure, either as alloy or core–shell. TiO2 particles with the deferent morphologies such as NPs, nanotubes, and nanorods have been synthesized using different reducing as stabilizing agents by sol–gel, electrochemical anodic oxidation, hydrothermal, electrospinning, chemical vapor deposition and spray pyrolysis [3-5] methods. Comparatively, the hydrothermal processing offers a promising approach due to its simple process, fast reaction and low cost, it may pave the way for novel TiO2 morphologies with the new properties. Herein, we are describing a simple and inexpensive technique to synthesize the nanocrystalline TiO 2 using the capping agent nitric acid via hydrothermal route. For the confirmation of TiO 2 particles, we have made various characterizations like UV-Vis spectrophotometer, XRD, TEM and EDS. These synthesis processes could be suitable for large scale production of NPs. Experimental details and methods Chemicals Titanium (IV) n-butoxide (TNB) [99 wt% liquid
analytical grade] was purchased from Alfa Aesar chemicals, India. Nitric acid (HNO3) (69 wt% analytical grade) was purchased from SD fine chemicals, India. De-ionized water (DW) is used in the preparation of all suspensions and solutions. Synthesis of TiO2 NPs The chemogenic synthesis of TiO2 NPs (CST) was carried out via hydrothermal route. In the typical synthesis of TiO2 NPs 15 ml nitric acid and 15 ml DW were taken in 50 ml beaker, stirred for 10 minutes at room temperature. Then 0.5 ml TNB was added dropwise to this mixture and stirred for 45 minutes. The solution was then transferred to 50 ml of Teflonlined stainless steel autoclave, the autoclave was sealed and placed in an oven heated up to 180 °C for 180 minutes, then the autoclave was cooled down to room temperature. Under the ambient conditions, the reaction mixture was centrifuged to collect the product; the product was washed continuously with DW and ethanol several times to remove the salts unbounded to the surface of the product. The final product was dried in an oven at 50 °C for 60 minutes. The product obtained is in the form of white color powder, which was used for various characterization techniques. Characterization techniques UV-Vis absorbance spectrum was measured using UV-Vis spectrophotometer (model: V-690 Jasco, K.U Dharwad) in the wavelength range 200–800 nm. The crystal structures of the sample was analyzed by XRD (model: Rigaku pro analytical, M.I.T Manipal) with Cu Kα radiation of wavelength 1.54060 A˚ at a scanning
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DAE-BRNS 63thrd Interdisciplinary International Symposium Symposium on Materials on Materials Chemistry,December Chemistry, December 7-11,2010,Mumbai,India 6-10, 2016, Mumbai, India rate of 0.02˚ per second in the range of 20˚ to 80˚, peak analysis was done using PCPDFWIN software. The surface morphology and nanostructure were examined using TEM (model: Hitachi 7500, STIC Cochin), along with corresponding selected area electron diffraction (SAED) pattern, it is operating at an acceleration voltage 200 kV. TEM image was analyzed using PIXEL imaging software. Elemental compositions were analyzed using EDS (model: NORAN System 7 X-ray Microanalysis System, University of Mysore, Mysore).
62.553°, 68.716° and 89.274° can be indexed to the (110), (101), (111), (210) (211), (220), (002), (301) and (330) crystal planes respectively. The comparison of 2θ values in observed (Figure 2) XRD patterns with those from the JCPDS data no.79-1640 confirms the formation of TiO2 having rutile phase and a tetragonal crystal structure. The Scherrer’s equation [7] is used to estimate the crystalline size of the NPs, estimated average crystalline size is 50.70 nm.
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