Isolation, Purification, and Application of Single Wall Carbon Nanotubes Using Biopolymer.

单壁碳纳米管(SWNTs)是一种新型的分子尺度管，其直径和手性决定了其独特的性质。然而，大多数原始的和可获得的单壁碳纳米管样品不仅含有单壁碳纳米管，而且还含有其他含碳杂质，如无定形碳、富勒烯、纳米颗粒和在合成单壁碳纳米管过程中作为催化剂引入的过渡金属。因此，我们开发了一种新的方法来纯化单壁碳纳米管(SWNTs)，方法是在空气中进行热处理，并将其分散在明胶或羧甲基纤维素(CMC)的水溶液中。通过电子显微镜、拉曼光谱和热重分析(TGA)等分析技术对所得单壁碳纳米管的纯度进行了评价。结果表明，明胶或CMC作为一种良好的分散剂，对碳纳米管束的剥离起到了很好的作用，从而制备出了质量相当高的碳纳米管。另一方面，通过催化分解乙醇制备了高石墨化的碳纳米纤维。该工艺采用Fe/Co双金属催化剂，采用脉冲激光沉积的方法在钨衬底上沉积金属催化剂颗粒。用扫描电子显微镜、透射电子显微镜、电子衍射仪和拉曼光谱对所制备的碳纳米纤维进行了表征。从电子显微镜观察，所合成的碳纳米管直径在40~100 nm之间，长度可达2μm，并在样品中观察到多壁碳纳米管。结果表明，脉冲激光沉积是制备纳米催化剂的有力工具。

The single wall carbon nanotubes (SWNTs) are novel molecular-scale tubes exhibiting unique properties which depend on their diameter and chirality. However, most of the raw and available SWNTs samples contain not only SWNTs but also other carbonaceous impurities such as amorphous carbon, fullerenes, nanoparticles, and transition metals that are introduced as a catalyst during the synthesis of the SWNTs. Hence, We have developed a novel method for the purification of single wall carbon nanotubes (SWNTs) by annealing in air and dispersing the SWNTs in an aqueous solution of gelatin or carboxymethylcellulose (CMC). The evaluation of purity of the resulting SWNTs was done by means of analytical techniques such as electron microscopy, Raman spectroscopy, and thermogravimetric analysis (TGA). As a result, it was revealed that the gelatin or the CMC played an effective role in exfoliation of the SWNT bundles as a good dispersion reagents and thereby, SWNTs with appreciably high quality were prepared.On the other hand, Highly graphited carbon nanofibers (CNFs) have been synthesized by catalytic decomposition of ethanol. The Fe/Co bimetalic catalyst was employed in this procedure and the metal catalyst particles were generated by the pulsed laser deposition on the tungsten substrate. The obtained CNFs were investigated by the SEM, TEM, Electron diffraction and Raman spectroscopy. From the electron microscope observation, the synthesized CNFs have diameters in rage of 40〜100nm and length was up to 2μm. The Multi Wall Carbon Nanotubes (MWNTs) were also observed in obtained sample. As a result, it was revealed that the pulsed laser deposition is powerful tool to produce the nano-particles of the catalyst.