The chirality structure of a single-walled carbon nanotube (SWNT) strongly depends on the composition of catalyst used in the chemical vapor deposition process. In this study, we develop a porous magnesia supported manganese-rhenium (MnRe/MgO) catalyst for chirality-selective synthesis of SWNTs. Detailed characterizations reveal that (6,5) tubes with a selectivity higher than 70% are grown from the Re-rich MnRe/MgO catalyst. By comparing the SWNT growth results with those of monometallic Mn or Re, the formation of sigma phase, an intermetallic compound occurring in transition-metal alloy systems, is revealed to be crucial for the dominant synthesis of (6,5) SWNTs. This work not only extends the application of sigma phase alloy for catalytic synthesis of SWNTs, but also sheds lights on the growth of SWNTs with a high chirality selectivity.

Bulk synthesis of single-walled carbon nanotubes (SWNTs) using solid catalyst has been challenging, despite of recent breakthrough in the chirality-specific growth on the flat substrate surface. In this work, we propose a porous magnesia support rhenium catalyst for bulk synthesis of SWNTs. It is found that the well-dispersed catalyst with a high melting point and the optimal chemical vapor deposition reaction conditions account for the growth of SWNTs. Detailed characterizations reveal the produced SWNTs are dominant in (n, n − 1) and (n, n − 2) species. Furthermore, by using a multicolumn chromatography post-growth separation method, SWNTs with three defined diameter ranges were obtained. This work guides the design of porous oxide supported catalyst for bulk synthesis and diameter-dependent sorting of SWNTs, which will ultimately help harness the extraordinary properties of SWNTs.