A Novel Mixed Reverse Microemulsion Route for the Synthesis of Nanosized Titania Particles~!2009-01-28~!2010-06-04~!2010-08-13~!

Abstract

The main objective of this work was to prepare nanosized titania (TiO 2) particles by mixed reverse microemulsion route. In this work titania was prepared by quaternary microemulsion system (water/surfactant/co-surfactant/ oil-phase). Span-80, Aerosol-OT, n-Propanol, Isooctane, and Titanium tetra isopropoxide (TTIP) were used as surfactant, co-surfactant, oil-phase and titania precursor respectively. The effect of water to surfactant ratio (w 0) on the size of titania particles was studied. The X-ray diffraction pattern shows the presence of pure Anatase phase with tetragonal crystal structure. The calculation of particle size using scherrer equation shows that the particle size of titania nanoparticles increases with increasing water to surfactant ratio. The TEM image exhibited spherical morphology and narrow size distribution of the nanosized titania particles. The nanoparticles thus prepared can find applications in i.) For gas sensing. ii.) Photo-electrodes for dye-sensitized solar cells. iii.) In removing the organic chemicals which occur as pollutants in wastewater effluents.

Annealing Effect on the phase Transformation in

“…A thermal treatment is necessary to improve the crystallinity of compounds. When TiO 2 powder is calcined at higher temperature, crystal structure transformations may occur, the transformation temperature depends on the nature and structure of the precursor and the preparation conditions [5].…”

“…Semiconductor nanocrystals have been widely studied for their fundamental properties [3], especially titanium dioxide (TiO 2 ). Nanosized titanium dioxide materials have been the focus of great interest because they exhibit modified physical-chemical properties in comparison with its bulk [2,4,5]. Inexpensiveness, excellent chemical stability nontoxicity, high photocatalytic property, a wide band gap and high refractive index of TiO 2 make it attractive for practical applications [6][7][8].…”

“…Inexpensiveness, excellent chemical stability nontoxicity, high photocatalytic property, a wide band gap and high refractive index of TiO 2 make it attractive for practical applications [6][7][8]. The uses and performance for a given application are strongly influenced by the crystalline structure, the morphology and the size of the particles [5]. There are three main crystalline polymorphs for TiO 2 rutile (tetragonal), anatase (tetragonal) and brookite (orthorhombic) [4,5,9], all crystallographic forms of nanocrystalline TiO 2 are of great importance from the view point of applications.…”

“…The uses and performance for a given application are strongly influenced by the crystalline structure, the morphology and the size of the particles [5]. There are three main crystalline polymorphs for TiO 2 rutile (tetragonal), anatase (tetragonal) and brookite (orthorhombic) [4,5,9], all crystallographic forms of nanocrystalline TiO 2 are of great importance from the view point of applications. Rutile has a high values of refractive index (2.7) and dielectric constant, so it is suitable for optical coating, as dielectric in thin film capacitors in microelectronic devices and as light scattering [6,8,10].Rutile is most important white pigment in paint and has other everyday uses as a whitener in toothpaste and the UV absorber in sunscreens [11].…”

“…The rutile structure is very compact and * Department of physics/ College of science for women/ University of Baghdad. thermodynamically most stable phase at all temperatures [8], whereas anatase and brookite phases are thermodynamically metastable and transform exothermally and irreversibly to the rutile phase upon annealing [4,5,13]. There are several pathways this phase transformation can take including: anatase to rutile, anatase to brookite to rutile, brookite to rutile, and brookite to anatase to rutile.…”