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.