New developments in the growth of 4 Angstrom carbon nanotubes in linear channels of zeolite template

We report new developments on the chemical vapor deposition growth of 0.4 nm singlewalled carbon nanotubes (SWCNTs) inside the linear channels of the aluminophosphate zeolite, AlPO4-5 (API), single crystals (0.4 nm-SWCNT@AFI). Ethylene (C2H4) and carbon monoxide (CO) were used as the feedstock. Polarized Raman spectroscopy was used to analyze the structure and quality of SWCNTs, both the radial breathing mode and G-band are much clearer and stronger than the samples grown by the old process which used template tripropylamine molecules for growing SWCNT@AFI. From the Raman spectra, it is clearly seen that the RBM is composed of two peaks at 535 and 551 cm(-1). By using the pseudopotential module in Material Studio to calculate the Raman lines, the 535 cm(-1) peak is attributed to the (5,0) SWCNTs and the 551 cm(-1) peak to the (3,3) SWCNTs. The abundance of (4,2) is relatively small. Thermal gravity analysis showed that while the samples grown by CO display less than 1 wt% of carbon, for the samples heated in C2H4 atmosphere the weight percentage of SWCNTs is around 10%, which implies similar to 30% of the API channels are occupied with SWCNTs, a significant increase compared with the previous samples. (C) 2014 Elsevier Ltd. All rights reserved