Chemical and morphological characterization of multi-walled-carbon nanotubes synthesized by carbon deposition from an ethanol–glycerol blend

• Alternative precursor (glycerol-ethanol blend) for multiwall carbon nanotubes synthesis was used.
• Two different MWCNT types (regular and bamboo-like) were obtained depending on synthesis temperature.
• At 900 °C prevailed the synthesis of bamboo-like MWCNTs.
• The higher the temperature of synthesis, the larger the diameter of carbon nanotube coming from an ethanol-glycerol blend.
• Crystal domain was larger for MWCNTs obtained at 900 °C, but the number of defects make them more susceptible to oxidation.

The results of this work indicated that the carbonaceous material obtained by catalytic chemical vapor deposition (CCVD) method using a glycerol–ethanol mixture as carbon source and LaNiO3 perovskite as catalyst has grown in entangled tubular arrangements and corresponds to multi-walled carbon nanotubes (MWCNTs) which morphology features will depend on temperature conditions. Thus, at 700 °C, thinner and well-defined MWCNTs with parallel graphene layers were observed, whereas at higher temperature (800 °C and 900 °C), bamboo-like MWCNT morphology prevails followed by an increase in their outer diameter. Although the last one is much more susceptible to oxidation in air compared to that obtained at 700 °C, the packing of the graphene layers and the crystal size domain (La) along the axial axis of the nanotube corresponds to highly organized material being accord to that observed by transmission electron microscopy (TEM) and Raman spectroscopy. Therefore, the reactivity of bamboo-like MWCNTs to oxidation can only be explained by the presence of local defects associated with the interconnections between compartments.

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