Zeolite-supported synthesis, solution dispersion, and optical characterizations of single-walled carbon nanotubes wrapped by boron nitride nanotubes.

Zeolite-supported carbon nanotube (CNT) synthesis provides a route for its mass production due to the porous surfaces accommodating a large number of catalytic particles and maintaining the fine particle sizes during high-temperature growth. Coaxial single-walled carbon nanotubes (SWCNTs) and boron nitride nanotube (BNNT) van der Waals heterostructures have been produced recently on the CNT thin-film template. To achieve a high yield of the one-dimensional heterostructure, BNNT-wrapped SWCNTs were synthesized on zeolite support coated with catalytic nanoparticles. They were then dispersed in solution and examined by absorption, photoluminescence, and Raman spectroscopy. A robust thermal stability enhancement was observed, and optical characterizations revealed the composition of dispersed SWCNTs wrapped by BNNTs before air annealing includes individual SWCNTs, BNNT-wrapped SWCNT bundles, and BNNT-wrapped individual SWCNTs. Furthermore, the outside wrapping by BNNTs caused a significant down-shift of the photoluminescence spectrum in semiconducting SWCNTs, suggesting that BNNT-wrapped SWCNTs can be preserved after harsh dispersion treatments. [ABSTRACT FROM AUTHOR]