Production of single-walled carbon nanotubes from methane over Co-Mo/MgO nanocatalyst: A comparative study of fixed and fluidized bed reactors

In this study, the performances of fixed and fluidized bed reactors in the production of single-walled carbon nanotubes (SWNTs) have been investigated. In both reactors, single-walled carbon nanotubes were grown by catalytic chemical vapor decomposition (CCVD) of methane over Co-Mo/MgO nanocatalyst under two different operating conditions. The synthesized samples were characterized by TEM, TGA and Raman spectroscopy. It is found that the performance of a fluidized bed in the synthesis of carbon nanotubes is much better than that of a fixed bed. The quality of carbon nanotubes obtained from the fluidized bed was significantly higher than that from the fixed bed and the former one with the I(D)/I(G) ratio of 0.11 while the latter one with the I(D)/I(G) ratio of 0.71. Also, the yield of SWNTs in the fluidized bed was 92 wt%, while it was 78 wt% in the fixed bed. These advantages of fluidized bed reactors for the synthesis of carbon nanotubes can be attributed to more available space for the growth of carbon nanotubes and more uniform temperature and concentration profiles.