Studies On The Synthesis And Characterization Of One-Dimensional Carbon Nano Materials By Chemical Vapor Deposition Methods

Since the discovery of carbon nanotubes (CNTs) by Iijima in 1991, carbon nanotubes have attracted much attention due to their scientific significance and potential technological applications. The synthesis, properties and applications of CNTs are one of the most active research fields. Developing new preparation methods and new systems of carbon nanotubes are very important topic in current research activities in the fields of physics, chemistry and materials science.In this article, single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), graphite nanorods were successfully prepared by chemical vapour deposition (CVD) method. The morphologies, sizes and structures of the products were characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), raman spectrum and X-ray diffraction (XRD). The main results are summarized as follows:Firstly, SWCNTs were prepared by CVD method using Fe/Mo/MgO as catalyst. The influence of reaction parameters, including reaction temperature, and types of catalyst is discussed. The role of Mo in the reaction and the formation mechanism of SWCNTs are analysed.Secondly, carbon dioxide was used as carbon source in the synthesis of MWCNTs by CVD method over Fe/CaO catalyst. TEM and raman spectroscopy results indicated that multi-walled carbon nanotubes with a perfect graphite structure were successfully prepared. The influence of the catalyst on the decomposition of carbon dioxide was also discussed. The activation of carbon dioxide in the synthesis of carbon nanotubes is the most crucial process. The using of carbon dioxide as carbon source and the water formed in the MWCNTs growing process are helpful for the decreasing of amorphous carbon produced in the products. Other influence factors such as temperature, catalyst support were also studied.Thirdly, graphite nanorods were prepared by CVD method using methane as carbon source at temperatures 865°C. XRD, TEM and Raman spectroscopy showed that the product is graphite nanorods of high purity. The formation mechanism of the graphitenanorods was studied. Base on the results of the synthesis of graphite nanorods, we discussed the formation mechanism of one-dimensional carbon nanomaterials in the CVD process.