Fabrication, Purification, and Characterization of Double-Wall Carbon Nanotubes via Pulsed Arc Discharge

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• 作者：Hiromichi Yoshida ; Toshiki Sugai ; Hisanori Shinohara
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：December 18, 2008
• 年：2008
• 卷：112
• 期：50
• 页码：19908-19915
• 全文大小：573K
• 年卷期：v.112,no.50(December 18, 2008)
• ISSN：1932-7455

文摘

Fabrication of high-purity double-wall carbon nanotubes (DWNTs) with purity more than 95% has been achieved by developing synthetic and purification methods. High-temperature pulsed arc discharge (HTPAD) is used to synthesize DWNTs with controlled combinations on catalysts of transition metals (Ni/Co/Fe) and rare earth metals (Y/La). The results show that both rare earth metals and cobalt concentrations are crucial to enhance production of DWNTs and to reduce that of residual single-wall carbon nanotubes (SWNTs). The as-produced DWNTs are purified by establishing a dispersion-assisted oxidation procedure. To optimize purification processes, stabilities against oxidation in terms of the number of layers (DWNTs and SWNTs) and of the diameters are investigated. The oxidation rate of DWNTs is twice as low as that of SWNTs with the same diameter of around of 1.6 nm at a suitable temperature. As the results of these optimizations, DWNTs with a purity of 95% have been obtained from as-produced 10% DWNT samples. To achieve this high purification with minimum loss of DWNTs, hybrid oxidation with hot air and refluxing in hydrogen peroxide have been also developed.