Single-walled B-doped carbon, B/N-doped carbon and BN nanotubes synthesized from single-walled carbon nanotubes through a substitution reaction

Bundles of single-walled boron-doped carbon (BxC1−x), boron- and nitrogen-doped carbon (BxC1−x−yNy) and boron nitride (BN) nanotubes were prepared by thermal treatment of a mixture of boron trioxide and bundles of single-walled carbon nanotubes at 1523–1623 K in a nitrogen flow. The (BxC1−x+BxC1−x−yNy)/BN nanotube yield ratio increased with decreasing temperature in the reaction zone. The nanotubes were characterised by using high-resolution transmission electron microscopy and electron energy loss spectroscopy. The diameter of the individual nanotubes in the resultant bundles was 1.2–1.4 nm, which was similar to the diameter of the starting C-nanotubes. The B/C ratio of the B-doped carbon nanotubes was of ⩽0.1, whereas the BN nanotubes exhibited a B/N stoichiometry of ∼1.0.