The Formation of SiO2 and TiO2 Nano-size Composite Materials in Gas Phase Combustion Synthesis
Date Issued
2007
Date
2007
Author(s)
Hsu, Chia-Cheng
DOI
zh-TW
Abstract
The study focuses on premixed CH4 +O2+N2 flame and adjusted ratio of TTIP/HMDSO for composing Titania/silica complex oxides (TiO2-SiO2). The experimental conditions include the equivalence ratio, the ratio of oxygen/nitrogen, the collecting height and the concentration of different precursors. The composing Titania/silica complex oxides mechanisms are studied by the flame observation, flame temperature, crystalline phase and particle sizes.
Flame color is affected by adjusting the ratio between two precursors. The main reason is that the TTIP changes the flame color from blue to red. However, HMDSO does not change the flame color. The higher equivalence ratio and the oxygen/nitrogen ratio cause higher flame temperatures. When two precursors are added, the flame temperature decreases due to both precursors causing endothermic reactions.
When the equivalence ratio, the ratio of oxygen/nitrogen and collecting height increase, the composite result of TiO2 phase of titania/silica complex oxides (TiO2-SiO2) is Rutile phase. Also, the amount of Rutile is increasing. In the aspect of particle size analysis, the higher equivalence ratio and the oxygen percentage cause temperature rise and more collision chances that lead to bigger particle size. Heterogeneous nucleation of SiO2 on the surface of TiO2 is the main reason of core-shell nanocmposites formation. In addition, the size of TiO2 nanoparticles of titania/silica complex oxides increases with the collecting height in the flame.
Subjects
TiO2-SiO2複合氧化物
前置物
TTIP
HMDSO
Rutile
Titania/silica complex oxides
Precursors
Type
thesis
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