the preparation of nano-sized tio2 by titanium tetraisopropoxide (ti(oipr)4) via sol-gelmethod using acid as a catalyst is investigated and the optimized conditions concerning theproportional amount of acid, water, alcohol is established by xrd and sem. the effect ofcalcination temperature on phase transformation of tio2 (rutile, anatase and brookite) wasdetermined by xrd. the smallest grain si...

the synthesis of titania via sol-gel method has been widely studied. in the present work, titania was deposited onto a titanium substrate via sol-gel method. different processing parameters such as the repetition number of dipping/heat treatment process and dipping time have been studied to obtain the homogenous titania coating. phase and microstructural evaluation of the powder and coating sam...

Rutile titania powders were synthesized via a sol-gel/hydrothermal process using nitric acid as the catalyst. A molar acid to alkoxide ratio of 10 and a water to alkoxide molar ratio of 250 produced 100% rutile powders when precipitated below 45 °C. Higher temperatures yielded initially either anatase or mixtures of anatase and rutile. Spherulitic growth produced cauliflower-shaped agglomerates...

The stability of surface structure and space-charge distribution in free TiO2 nanoparticles are investigated for both rutile and anatase phases using a variable-charge interaction potential in which atomic charges vary dynamically depending on their environment. We find the dynamic charge transfer: ~i! enhances atomic diffusion at surfaces of the spherical nanoparticles at high temperatures; an...

The photocatalytic behavior of titania coatings is largely determined by their crystalline structure. Depending on deposition conditions, though, titania may form amorphous, brookite, anatase or rutile structures, with anatase or anatase/rutile mixed phase structures showing the highest levels of activity. Anatase is activated by UV light and, consequently, there is a great deal of interest in ...

Using a simple hydrothermal synthesis, the crystal structure of TiO2 nanoparticles was controlled from rutile to anatase using a sugar alcohol, D-sorbitol. Adding small amounts of D-sorbitol to an aqueous TiCl4 solution resulted in changes in the crystal phase, particle size, and surface area by affecting the hydrolysis rate of TiCl4. These changes led to improvements of the solar-to-electrical...

Photoactive films consisting of pure anatase, brookite or rutile TiO2 were prepared by dip coating from water dispersions obtained by using TiCl4 as the precursor under similar mild experimental conditions.

This paper describes high porosity titanium dioxide (TiO2) films deposited via atmospheric pressure chemical vapour deposition (APCVD) using tetraisopropyl titanate at deposition temperatures (Tdep) of 250C and 450C in excess water vapour. Films deposited at low Tdep exhibit a very low refractive index (nfilm) and high porosity (), up to 87% of the bulk rutile phase. High-temperature sinteri...