Efficient mixed metal oxide routed synthesis of boron nitride nanotubes

Abstract

Boron nitride nanotubes (BNNTs) were successfully synthesized by a simple annealing process. Amorphous boron powder (B) was used as boron source to react with various metal oxide mixtures (V₂O₅/Fe₂O₃ and V₂O₅/Ni₂O₃). V₂O₅ acts as an efficient promoter in the synthetic process due to its highly oxidizing and reducing properties. The Fe₂O₃ and Ni₂O₃ act as catalysts in combination with the B/V₂O₅ system to achieve highly crystalline BNNTs at 1100 °C. The morphology and crystalline nature of the BNNTs were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The observations revealed the hexagonal-BN (h-BN) phase of the BNNTs, with a highly crystalline tubular structure. This method proved to be simple and economical, using B/V₂O₅/Fe₂O₃ and B/V₂O₅/Ni₂O₃ mixtures for the large scale production of BNNTs.