| Summary: | 碩士 === 遠東科技大學 === 機械研究所 === 96 === This study is mainly about the synthesis of barium carbonate (BaCO3) nanowires and nanoplates via the organic-phase thermal decomposition process using barium oleate or precursors. The barium oleates were obtained by dissolving barium oxide in hot oleic acids at 300℃. The characterization of barium oleates were carried out by using XRD, TGA, and FT-IR. Under proper decomposition temperature, the precursors were decomposed and produced monodispersive barium carbonate nanowires nanoplates in a mixture of oleic acid and oleylamine at 350℃ under N2.
The morphology of the product can be controlled by the ratios of oleic acid and oleylamine. Nanowire was prepared under higher ratio of oleylamine to oleic acid while nanoplate was synthesized in the environment of lower ratio of oleylamine to oleic acid. Particle size distribution pattern and structure behaviors are characterized by transmission electron microscopy, powder X-ray diffraction with single crystal-database (ICSD), and simulation software: Single Crystal, Crystal Diffract. The morphology of BaCO3 nanowire and nanoplate were characterized by TEM. Width of the nanowire particles is 7nm ± 0.5nm and size of the nanoplate particles ranges from 50nm to several nanometers. The long axis of the nanowire is c axis of orthorhombic witherite structure. Under lower ratio of oleylamine to oleic acid, nanoplate of trigonal or monoclinic crystal system can be prepared due to the first degree oleamide which results in the change of morphology and structure. However, the final stable structure is still orthorhombic system under room temperature.
The addition of NaF in the above reaction for BaCO3 nanowires can lead to the formation of BaF2 nanowires where optical property was characterized by UV-vis and PL spectrometer.
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