Crystallographic Order in Multi-Walled Carbon Nanotubes Synthesized in the Presence of Nitrogen

Multi‐walled carbon nanotubes were synthesized by chemical vapor deposition from pure toluene and toluene/diazine mixtures using ferrocene as a catalyst precursor at 760 °C. As recently announced,[1] characterization of the resulting nanotube films showed that, unlike pure carbon nanotubes, those grown in the presence of nitrogen have an extremely high degree of internal order, both in terms of the uniform chirality in the nanotube walls and of the crystallographic register between them. Here, the structure, defects, and morphology of the nanotubes were analyzed in depth using advanced electron microscopy techniques, and compared with existing models and observations. Nitrogen, which seems to be responsible for the dramatic structural order, was found to segregate preferentially within the core of the nanotubes. Made to order: Multi‐walled carbon nanotubes synthesized by chemical vapor deposition from toluene/diazine have a high degree of internal order. The structure, defects, and morphology of the nanotubes were analyzed by advanced electron microscopy techniques. Bamboo‐ and weblike structures are formed (see energy‐filtered TEM image). Nitrogen, which seems to be responsible for the dramatic structural order, segregates preferentially within the core of the nanotubes.