| Summary: | 碩士 === 遠東科技大學 === 機械研究所 === 95 === This study demonstrated a facile method for the fast synthesis of CeO2 nanoplates and nanowires via the thermal decomposition of a mixture of cerium acetate, oleic acid, oleylamine, and 1-octadecene under different atmospheres. The results revealed that the atmosphere is a important parameter for the fast formation of CeO2 Nanocrystals. Under optimized condition and atmosphere of air, the reaction time can be reduce form hours to only 10 minutes.
Results also appeared that both oleic acid and oleylamine are essential to the successful synthesis. Oleic acid is helpful to the dissolution of precursor, and oleylamine is helpful to the precipitation of the crystalline CeO2 nanophase.
The oleylamine can be added in two different ways which have effect on the shapes of the products : (method 1)-- oleylamine was added in the begging of experiment, under which plate-like CeO2 can be obtained at 250℃ for 10 minutes. (method 2)-- oleylamine was injected at 250℃, under which, the wire-like CeO2 can be obtain after 10 minutes.
In method 1, the evolution of reaction was also monitored at different reaction temperatures. It appeared at lower temperature (180℃) the product preffered in a form of wire. Raising the temperature to 200℃, some particle with appearance of combined wire and small plate appeared.
At 250℃, the nanoparticles have transformed to be plate-like. In method 2, the evolution upon different reaction time was also monitored.
It appeared that the as-formed nanowires were not stable upon time evolved. The nanowires were gradually transformed to CeO2 plate-like phase.
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