Oxidation of multiwalled carbon nanotubes by nitric acid
Oxidation of multiwalled carbon nanotubes by nitric acid
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DOI：
10.1016/j.carbon.2005.06.019
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发表时间：
2005-12-01
期刊：
影响因子：
10.9
通讯作者：
Akaska, T
中科院分区：
文献类型：
--
作者：
Rosca, ID;Watari, F;Akaska, T
使用样品重量、拉曼光谱监测硝酸中多壁碳纳米管的氧化。溶解度。形态和排列。评估了酸浓度、温度和氧化持续时间对监测参数的影响。提出了一种基于光学显微镜的新方法，用于测定浓水悬浮液中多壁碳纳米管的溶解度。研究表明，溶解度不仅取决于多壁碳纳米管上的官能团，还取决于纳米管消化过程中产生的官能化无定形碳。只有在浓酸（> = 60％）中长时间暴露（24-48小时）后才能获得高溶解度（20-40毫克/毫升）。但在这些条件下，60-90% 的多壁碳纳米管会丢失。此外，氧化 48 小时后，多壁碳纳米管强烈破碎并被无定形碳覆盖。结果发现，溶解度与拉曼光谱中 G 和 D 带的面积比有很好的相关性，MWCNT 薄膜的 SEM 检查显示氧化 24 小时后排列延长。 (C) 2005 Elsevier Ltd. 保留所有权利。
The oxidation of MWCNTs in nitric acid was monitored using sample weight, Raman spectrum. solubility. morphology and alignment. The influence of the acid concentration, temperature and oxidation duration on the monitored parameters was assessed. A new method, based on optical microscopy is proposed for the determination of MWCNT solubility in concentrated aqueous-suspensions. The investigations revealed that the Solubility is determined not only by the functional groups on the MWCNT, but also by the functionalized amorphous carbon generated during the digestion of the nanotubes, High solubility (20-40 mg/ml) is obtained only after prolonged exposure (24-48 h) in concentrated acid (>= 60%). But in these conditions 60-90% of the MWCNTs are lost. Furthermore the MWCNTs are strongly fragmented and covered by amorphous carbon after 48 h of oxidation. It was found that the solubility correlates well with the area ratio of the G and D bands from tile Raman spectrum, SEM examination of the MWCNT films showed extended alignment after 24 h of oxidation. (C) 2005 Elsevier Ltd. All rights reserved.