CHEM01200604009 Sreejith Kaniyankandy - Homi Bhabha ...

87
3. 2. Experimental Section
3.2.1. Materials: Titanium(IV) tetraisopropoxide {Ti[OCH(CH 3 ) 2 ] 4 } (Aldrich, 97%),
benzophenone (Aldrich), Trioctylphophineoxide, TOPO (Aldrich), toluene (Aldrich),
methanol (Aldrich), acetone (Aldrich).
3.2.2. Preparation of ultrafine TiO 2 nanoparticles:
The ultrafine TiO 2 nanoparticles have been prepared by arrested precipitation method.
Briefly 15 gm of benzophenone was heated to a temperature of 200°C in an Ar atmosphere.
This temperature was held for ½ hour and further heated to 300°C. At this temperature,
benzophenone itself behaves as solvent. Titanium tetraisopropoxide (distilled before the use)
was rapidly injected into above solvent. On injection the solution temperature decreases by
15°C and maintained the reaction mixture at 280°C for further 15 min. The solution was
cooled to 80°C and methanol was added for the precipitation of TiO 2 . The precipitates were
centrifuged and repeatedly washed with methanol and acetone and dispersed in toluene and
then re-precipitated 3 times and dried in the ambient for further studies. The nanoparticles
capped with and trioctylphosphine oxide (TOPO) and benzophenone will be referred to as T-
TiO 2 and B-TiO 2 hereafter.