酸处理对多壁纳米碳管形态的影响

文中研究了酸处理对多壁纳米碳管形态的影响。分别用浓硝酸及浓硫酸和浓硝酸混合酸对未经石墨化多壁纳米碳管(MWCNTs)和石墨化多壁纳米碳管(MWGNTs)进行处理,讨论了不同处理时间,不同酸体系对不同碳管的处理效果,并采用TEM对其进行形态分析。结果发现,用硝酸长时间处理MWCNTs使纳米碳管发生短切,长径比变小,并且侧壁被整层剥离,管壁变薄;硝酸对MWGNTs的短切与剥离现象不明显。硝酸和硫酸的混合酸在0.5h内就可以将MWCNTs氧化殆尽,而使MWGNTs氧化殆尽则需要2h。在短切过程伴随着可以将多壁纳米碳管的管壁整层剥离的现象,用硝酸处理MWCNTs时该现象比较明显,处理MWGNTs时效果不明显;而混酸的氧化速度太快,处理两种多壁纳米碳管过程中的短切与剥离现象均不明显。

Effect of acid treatment on the morphology of multi-wall carbon nanotubes

The effect of acid treatment on the morphology of multi wall carbon nanotubes was studied. The multi wall carbon nanotubes (MWCNTs)and the graphitic multi wall carbon nanotubes(MWGNTs) made by a catalytically floating method were treated with a nitric acid and a mixed acid of sulfuric acid &; nitric acid. The effect of the time and acid system on the different carbon nanotubes were discussed and the results were characterized by TEM. The results indicate that the MWCNTs are cut and peeled after long time treatment by nitric acid and the walls of the carbon nanotubes are cut and peeled which results in mixed acid of the aspect ration decrease and the side-wall thinner,However,the MWGNTs ate only opened at ends by nitric acid and the phenomena of cutting and peeling are not much clear.compared with 2h for the MWGNTs,a results in sulfuric acid/nitric acid burned all the MWGNTs in much shorter time(0.5h).