Morphological variation of multiwall carbon nanotubesin supercritical water oxidation

Multiwall carbon nanotubes (MWNTs) with different morphology were prepared using supercritical water (SCW) oxidation and investigated by transmission electron microscope (TEM) and electron energy-loss spectroscopy (EELS). TEM results indicate that the peeling and sharpening of MWNTs are influenced by the etching process in SCW oxidation, of which oxidation time and amount of oxygen used is crucial. A simplified etching model is proposed, which indicates that the difference of mean etching rate between two adjoining blocks causes the morphological variation of MWNTs. The EELS results show change in characteristic energy-loss peaks as a function of total shell numbers along longitudinal axis of individual peeled tube.

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