| Summary: | 碩士 === 國立中正大學 === 化學工程所 === 97 === This research is devoted to synthesize carbon nanotubes by cold-walled CVD. The study was divided into two parts : synthesis of single walled carbon nanotubes using silica-supported metal catalysts and synthesis of double and thin walled carbon nanotubes using novel catalysts.
In the first part of the research, we synthesized bundle-like single walled carbon nanotubes using Co-Mo/SiO2 bimetallic catalysts. The Co : Mo molar ratio is 48 : 1. Bimetallic Co-Mo catalysts on amorphous silica formed nanostructures that were catalytically active at the growth temperature. Experimental parameters, such as reaction temperature, reaction time, reaction pressure, and Rm (H2/C2H2), were discussed for imporving the purity of single walled carbon nanotubes.
In the second part of the research, zirconium was used as catalyst to grow carbon nanotubes by vapor-liquid-solid (VLS) mechanism. The result showed that the CNT growth mechanism using zirconium at 850 ℃is bottom-growth model, while the growth mechanism of zirconium at 900 ℃ is tip-growth model. Double and thin walled carbon nanotubes can be prepared at 900 ℃ for 7 min.
Field emission scanning electron microscopy (FE-SEM), high resolution transmission microscopy (HR-TEM), energy dispersion X-ray spectroscopy (EDS), atomic force microscopy (AFM), and Raman analysis were carried out to characterize the morphology, structure, crystallography and surface roughness of the carbon nanotubes.
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