Crystallization and precipitation mechanism of titanium (IV) oxide under the solvothermal condition and the effect of second element on titanium (IV) oxide products

Abstract

The crystallization and precipitation mechanism of titanium (IV) oxide on the solvothermal reaction in organic media (1,4 butanediol, toluene) at 300 ํC under autogenous pressure was studied to yielded a nanocrystallite anatase titanium (IV) oxide. The physical properties and thermal stability of titanium (IV) oxide depended on the preparation mechanism. Titanium (IV) oxide synthesized in 1,4 butandiol yielded the anatase crystal due to the crystallization mechanism. On the other hand, titanium (IV) oxide synthesized in toluene yielded the amorphous phase due to the precipitation mechanism and transformed to anatase crystal with increasing the reaction time. For varying the reaction time, the crystallite size increases with an increasing the reaction time in both solvents. Titanium (IV) oxide synthesized in toluene showed a higher specific surface area than that synthesized in 1,4 butanediol with the same crystallite size. However, titanium (IV) oxide synthesized in 1,4 butanediol had a good thermal stability. Doping a second element, such as silicon, aluminium, phosphorous, in the starting material could improve the thermal stability. The crystallite size of modified titanium (IV) oxides were smaller than that of a pure titanium (IV) oxide. In addition, morphology of the modified titania depended on the doped second element.