CO₂-Assisted SWNT Growth on Porous Catalysts

The effect of CO 2 on the synthesis of single-walled carbon nanotubes (SWNTs) by methane decomposition on a Fe/Mo/MgO porous catalyst was investigated. Characterizations of the change in methane conversion with time, XRD and SSA of the catalyst, Raman spectroscopy, TGA, and the specific surface area (SSA) of SWNTs showed that CO 2 inhibited the formation of amorphous carbon around the catalyst and also interacted with the MgO support of the catalyst, which decreased its particle size and increased the SSA of the catalyst. The result was an increase in the yield, purity, and SSA of SWNTs. These results indicated that the limited and small space in the pores of the porous catalyst made it difficult to increase the SWNTs in high yield. The addition of CO 2, by destroying the structure of the catalyst and decreasing the catalyst size, provides a new route to increase the yield, purity, and SSA of SWNTs.