Production of N-doped carbon nanotubes using α- and β-cyclodextrins: The effect of solubility

Carbon nanotubes (CNTs) doped with nitrogen (N) were prepared via a floating catalyst procedure using ferrocene (FcH), dimethylformamide (DMF) and cyclodextrin (CD) moieties in order to explore CD solubility effects on the preparation of nitrogen doped carbon nanotubes (N-CNTs). Two common types of CDs (α-CDs and β-CDs containing 6 and 7 glucopyranosyl units, respectively) were employed in the synthesis of ‘bamboo-shaped’ N-CNTs. The experimental data demonstrate that N-doping of the CNT lattice by the pyrolysis of CD molecules in DMF in the presence of Fe nanoparticles results in the incorporation of substitutional N into the C hexagonal network. Indeed, the structural configuration and physicochemical properties such as solubility and volatility of precursors influence the morphology of the final product (e.g. CNT diameters, yields, compartments sizes) in Fe catalyzed reactions through a series of decomposition processes.

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► Doped carbons achieved using CD molecules.
► Bamboo structures (closer compartments) observed in the nanotube main axis.
► Solubility of precursors have a significant role in tube formation.
► Decomposition patterns of CDs affect growth.
► α-CDs give enhanced N-CNT growth.