Production of bamboo-type carbon nanotubes doped with nitrogen from polyamide pyrolysis gas

Bamboo-type carbon nanotubes (BCNTs) doped with nitrogen were produced by catalytic chemical vapor deposition from the effluent gases resulting from pyrolysis of polyamide 6.6. This polymer provides the carbon and nitrogen source and allows to obtain enough hydrogen during its decomposition for the carbon nanotubes (CNTs) production without prior catalyst reduction. The influence of pyrolysis and growth temperatures was studied in order to obtain the best quality CNTs. Transmission electron microscopy, X-ray diffraction, and Raman spectrometry showed that the best results were obtained at 900 °C pyrolysis temperature and 750 °C growth temperature, since the presence of amorphous carbon was negligible and the best crystalline degree was obtained. These BCNTs had from 5 to 20 layers and their arcs of bamboo-like compartments had from 3 to 15 layers. They had 20 nm in diameter and lengths typically on the order of micrometers.