Multi-step purification of multi-walled carbon nanotubes (MWNTs)

• Main Authors: Jian-Kai Huang, 黃建凱
• Other Authors: 鄭如茵
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/w4z4d2

碩士 === 國立臺北科技大學 === 有機高分子研究所 === 94 === In this study, we propose an effective method to purify multi-walled carbon nanotubes (MWNTs). The method involves ultra-sonication, bromination, thermal oxidation, and chemical etching in three different acid solutions, that is, HCl, HNO3 + HCl, and HCl + HF. We find that bromination before thermal oxidation can help to remove impurities in MWNTs such as amorphous carbon. In addition, thermal oxidation before chemical etching can remove metal catalysts more effectively. However, in this way the lowest yield of MWNTs may result. Using our purification method, the purity of MWNTs is best improved from ~85% to ~98%. In order to show the open tips of MWNTs after thermal oxidation, our purified MWNTs are characterized by transmission electron microscopy (TEM). We also use Raman spectroscopy to measure the effect of bromination before thermal oxidation. Finally, energy dispersive spectroscopy (EDS) as well as thermogravimetric analysis (TGA) are used to analyze the chemical composition and mass fraction of residual metal catalysts in MWNTs after chemical etching in acid solutions.