以多重步驟純化多層奈米碳管

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

黃建凱(Jian-Kai Huang)

指導教授 ： 鄭如茵

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2006年)

摘要

本實驗以各種方法純化多層奈米碳管，其中包括超音波震盪、溴化、氧化和使用三種不同酸液組合進行酸化處理，分別為HCl、HNO3 + HCl和HCl + HF。發現溴化之後再行氧化可有效去除amorphous carbon ，氧化之後再行酸化則可去除較多殘餘金屬催化劑，而經過的酸化步驟愈多殘餘金屬催化劑量愈少，相對的產率也較低，且以第三種混合酸液處理結果其殘餘金屬催化劑量最少。最佳的實驗結果為純度~85%升至純度~98%的多層奈米碳管。我們利用穿透式電子顯微鏡(TEM)來觀察奈米碳管純化後的特徵與氧化後造成碳管頂端裂解的情形；用拉曼光譜(Raman spectroscopy)來分析溴化與無溴化之後進行氧化步驟所得的效果；用能量分散光譜儀(EDS)來鑑定殘留在多層奈米碳管上的金屬催化劑種類，最後利用熱重損失分析儀(TGA)來測量經過不同酸液處理後剩餘金屬催化劑與多層奈米碳管的重量比例。

關鍵字

多層奈米碳管 ； 溴化

並列摘要

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.

並列關鍵字

MWNTs ； bromination

參考文獻

[36] 洪昭南，徐逸明，王宏達，「奈米碳管結構及特性簡介」，中華化學工程學

[1] S. Iijima, Nature 1991, 354, 56.

[11] S. Iijima, T. Ichibashi, Nature 1993, 363, 603

[13] T.W. Ebbesen, H. Hirua, J. Fujita, Chem. Phys. Lett. 1993, 209, 83.

[16] T.W. Ebbesen, P.M. Ajayan, Nature 1992, 358, 220.