The Preparation And Separation Of Single-Walled Carbon Nanotubes And Its Application In Modified Electrode

The single-walled carbon nanotubes (SWCNT) have remarkable electrical, mechanical and thermal properties because of their unique structure, special physical and chemical properties, offering the possibilities of wide promising applications in various fields, such as electronic device, carbon nanotubes reinforced composites, biomedicine and military. However, in the SWCNT prepared by the available methods, m-SWCNT and s-SWCNT exist in mixed state, which limits the advanced applications of SWCNT in many fields, such as electronics and photoelectricity. Therefore, how to achieve separation of m-SWCNT and s-SWCNT effectively, is an enormous challenge.This dissertation consists of the following sections:a) SWCNT were synthesized by decomposing CH4 over the Co/MgO catalyst. The preparation craft was optimized by adjusting the reaction temperature and gas flow rate. The technique of purifying raw SWCNT was developed by acidification-air oxidation process. The high quality SWCNT was obtained after purification.b) We have successfully separated the SWCNT efficiently using agarose gel electrophoresis method. The results were characterized and analyzed with UV-Visible-Near Infrared (UV-Vis-NIR) absorption spectroscopy and Raman spectra. We also investigated the probable factors which could affect the separating efficiency of SWCNT. The results show that m-SWCNT and s-SWCNT can be successfully separated by the proposed method.c) The effects of NaCl and PVP on the separation results of m-SWCNT and s-SWCNT were investigated through adding NaCl or PVP into the system to change the adsorption properties of the surfactant micelles on the surface of SWCNT. On the basis of the experiments, the separation mechanism of the SWCNT by agarose gel electrophoresis method was discussed preliminarily. The results indicate that the specific interaction between the s-SWCNT and the agarose and the different adsorption behavior of SDS on the surface of m-SWCNT and s-SWCNT are two key factors that lead to the separation of m-SWCNT and s-SWCNT.d) The glassy carbon(GC) electrodes modified with SWCNT, m-SWCNT and s-SWCNT film were fabricated and their electrochemical behaviors were investigated by cyclic voltammetry. The comparison of cyclic voltammetric behaviors between the bare GC and the modified electrodes in phosphate buffer solution (pH=7.0) containing dopamine(DA) was also explored. The results indicate that the modified electrodes exhibit perfect electrocatalytic abilities to DA. At last, the SWCNT-GC electrode shows excellent electrochemical discrimination to DA and ascorbic acid(AA). DA can be selectively determined in the presence of AA.