A robust Co_xMg_1-xO catalyst for predominantly growing (6, 5) single-walled carbon nanotubes

Chirality-controlled growth of single-walled carbon nanotubes (SWCNTs) by chemical vapor deposition (CVD) is one of the most challenging tasks in carbon nanotube synthesis field. During CVD growth, the catalyst plays crucial roles in governing SWCNT nucleation thermodynamics as well as growth kinetics. However, the performances of catalyst are generally sensitive to the metal loading amount in the catalyst and the reaction conditions, like the partial pressure of carbon source and the reaction time. In this work, we have systematically investigated a robust Co_xMg_1-xO solid solution, which can predominantly yield (6, 5) SWCNTs in a wide range of Co concentration, with a diversity of CO concentrations or a broad-ranging reaction time. Besides, the effect of reaction temperature on SWCNT chirality distribution is demonstrated, the mechanism of which is clarified with the assistance of environmental transmission electron microscopy. Finally, the chirality distribution of SWCNTs grown using CH₄ as the carbon source is presented. The effects of carbon sources are discussed in view of SWCNT growth mode.