High-quality single-walled carbon nanotubes (SWNTs) were synthesized on layered double hydroxides (LDHs) containing Fe and FeCo by CO chemical vapor deposition (CVD). Systematic investigations were performed to study the effects of temperature and catalyst composition on the diameter and chirality distributions of SWNTs. It was revealed that both catalysts produced subnanometer SWNTs at low reaction temperatures, correlated with the catalyst performances and reaction parameters. Particularly, SWNTs with enriched (6, 5) species were synthesized at 600 °C from LDHs containing bimetallic FeCo. Besides, the SWNT chirality distribution was further narrowed by a two-phase extraction method and the extracted (6, 5) SWNTs occupy about 57% of all semiconducting species. This work extends the development of robust LDH-based catalysts for chirality-selective synthesis of SWNTs, which paves the way to large scale production of subnanometer SWNTs for potential applications in electronics and optoelectronics.
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