Influence of Air Oxidation on the Surfactant-Assisted Purification of Single-Walled Carbon Nanotubes

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• 作者：Alejandro Anso虂n-Casaos ; Mo虂nica Gonza虂lez ; Jose虂 M. Gonza虂lez-Domi虂nguez ; M. Teresa Marti虂nez
• 刊名：Langmuir
• 出版年：2011
• 出版时间：June 7, 2011
• 年：2011
• 卷：27
• 期：11
• 页码：7192-7198
• 全文大小：821K
• 年卷期：v.27,no.11(June 7, 2011)
• ISSN：1520-5827

文摘

Arc discharge single-walled carbon nanotube (SWCNT) soot was treated under different experimental conditions including gas- and liquid-phase oxidation, heat treatment in an inert gas, and hydrogen gasification. Afterward, the samples were dispersed in a surfactant and centrifuged at a moderately high speed. Near-infrared spectra of all the dispersions were compared with that of raw SWCNT soot. The relative intensity of SWCNT characteristic spectral bands strongly increased for air-oxidized samples after centrifugation, while it did not substantially change for samples oxidized with nitric acid or reduced with hydrogen. The relative SWCNT spectral intensity was associated to the sample purity through the so-called purity index, which was calculated from the S₂₂ band transition of semiconducting SWCNTs. Air-oxidized samples experienced a 7-fold increase in the purity index during centrifugation, while it increased by only 2鈥? times for nonoxidized samples. Air oxidation specifically improves the preferential stability of SWCNTs over carbonaceous impurities in the dispersions, leading to the highest purity index values reported so far.