Hi everyone,
I Left my TiO2 sample in the Muffle with heating rate of 10C per min, 47mins from 20C to 500C and then 1 hour in 500C.
I expected the pure white TiO2, but on the top of the crucible, the powder was gray! (I repeated the experiment for 4 times with changing the parameters like different timing of Oven, or leaving TiO2 for one night in Room Temperature, but after putting in Muffle it was always gray!
I would appreciate you if you inform me how can I obtain pure white TiO2.
Dear Hedieh,
Are you using every time the same muffle? Maybe it is just contamination from muffle? I had experience when the muffle was dirty from previous experiments.
Best,
Halyna
What is more, probably, you have not achieved complete hydrolysis of titania precursor and this gray part is decomposed organics. I synthesized titania by the procedure below and obtained a very nice material:
The bare titania TiO2 was synthesized by an adjusted in situ sol-gel process. Briefly, 1.87 g of Ti(IV)isopropoxide (TTIP) (97%, Sigma Aldrich) was added to isopropanol (60 mL, Merck absolute, p.a.) and stirred for 30 min at 1000 rpm. After dropwise addition of 1.14 g HNO3 (65% Merck) and 12.4 mL water (MilliQ), the solution was sonicated for 4 h at room temperature. The HNO3 was added to start and accelerate the reaction while sonicating. The turbid, gel-like solution was placed in a Petri dish and stored until the liquid was evaporated. The dried, residual titania was calcined for 5 h at 500 °C in a flow of air, with a heat ramp of 30 °C·min-1 (Ströhlein Instruments HTC 1600).
Hope this info was helpful ;) Good luck!
H.
Dear Halyna Bodnar Yankovych
Thanks for your answer,
I also guessed it is because of the muffle, but I will try your procedure!
Sincerely,
Hedieh
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