| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 94 === Previous studies show that TiO2 crystal phase purity may be effectively controlled by the oxygen concentration in the Bunsen burner. Under flow rate O2/N2=20/80, the weight percent of rutile phase is nearly 100%. On the contrary, it is hard to control the crystal purity phase on the flat burner because of its irregular porous medium. Thus, the modified Hencken burner with regular flow channel, which is designed with characteristics of the Bunsen burner to control TiO2 crystal phase purity and particle size for possible mass production. In the modified Hencken burner, the titanium precursor TTIP was fed into the flame by a carrier N2 flow through a heated TTIP bath. Particles synthesized in the flame were characterized for their morphology, crystal phase purity, and their size, by transmission electron microscopy, and X-ray diffraction. The influence of flame type, flame length, TTIP concentration and O2/N2 molar ratio on crystal phase purity and particle size will be studied in detailed. Under the flow rate O2/N2=20/80, the rutile phase of nanoparticle is as high as 96%. Results also show that the size of TiO2 nanoparticles is highly depending on the TTIP loading and the collecting height in the flame. The range of TiO2 particle size averages from 100nm to 500nm were found under different operation parameters. The modified Hencken burner with shorter flame length is attributed to a decrease in particle reaction time and reduced particle collision frequency in a lower collecting height of the flame.
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