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Further Studies on Preparation of Novel Carbon Nanomaterials by DC Arc Discharge

Author: XuYan
Tutor: Cui
School: Tianjin University
Course: Physical and chemical
Keywords: DC arc discharge Novel carbon nanomaterials Carbon source Nitrogen temperature Substrate position SEM TEM
CLC: TB383.1
Type: Master's thesis
Year: 2010
Downloads: 59
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Abstract

Carbon nanomaterials is an important branch of nanomaterials and the correlative researches have now become one of the most active international frontiers. In this dissertation, the DC arc discharge method under nitrogen atmospheres was adopted, the effects of carbon source, temperature, and position of the substrates on the morphology and yields of the products were investigated. The morphology and microstructure of the products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), respectively. The carbon sources used for DC arc discharge were selected through the calcination experiments.The results of SEM characterization show that the quasi-network structure formed on the substrate put above and under the arc discharge region (ADR) is more obvious, when the carbon black was used as carbon source instead of graphite being used, but it is just opposite if the substrate was put at one side of the ADR. The quasi-network structure formed on the substrate put above and at one side of the ADR is more obvious, when the nitrogen inlet temperature was 800℃instead of being room temperature, but it is opposite if the substrate was put under the ADR and the carbon black was used as carbon source. The effect of the position of the substrate on the morphology of products is no obvious regularity. In most conditions, the spherical products with the surface similar to that of animal stomach were formed on the substrate, but there was no evident regularity.The results of TEM characterization present that the size of the nanoparticle formed on the substrate put at one side of and under the ADR is smaller, when the carbon black was used as carbon source instead of graphite being used, but it is just opposite if the substrate was put above the ADR and the nitrogen inlet temperature was at room temperature. The size of nanoparticle formed on the substrate put above the ADR is smaller, when the nitrogen inlet temperature was at room temperature instead of 800℃, but it is opposite if the substrate was put under the ADR. The effect of the position of the substrate on the morphology is that the main products formed on the substrate put position above the ADR are nanoparticles, but there are still small amount of nanotubes and some single crystal sheets in most cases on the substrates put at one side of and under the ADR. The results of calcination experiments show that carbon black and graphite samples were completely oxidized at the temperatures of 540℃and 730℃, respectively, so both of them can be used as carbon source of the DC arc discharge. Activated carbon was not completely oxidized even if the temperature reached 750℃, so it could not be used as carbon source of the DC arc discharge.The research results in this dissertation inaugurated the new approaches which can be used to prepare novel kinds of carbon films and nanomaterials, and have an importment practical significance for the research in the related fields.

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