(n,m) selectivity of single-walled carbon nanotubes by different carbon precursors on Co-Mo catalysts

Single walled carbon nanotubes (SWCNTs) were synthesized using four different carbon precursors including CO, C₂H₅OH, CH ₃OH, and C₂H₂ on Co-Mo catalysts. Semiconducting (n,m) abundance was evaluated by a method based on a single-particle tight-binding theoretical model taking into consideration the relative photoluminescence and absorption quantum efficiency for specific (n,m) tubes. (n,m) abundance determined in photoluminescence analysis was used to reconstruct the near-infrared E^s₁₁ absorption spectra. Carbon precursor pressure was found to be the key factor to the chirality control in this study. Narrowly (n,m) distributed SWCNTs can only be obtained under high-pressure CO or vacuumed C₂H₅OH and CH ₃-OH. The majority of these nanotubes are predominately in the same higher chiral-angle region. The carbon precursor chemistry may also play an important role to obtain narrowly (n,m) distributed SWCNTs. (n,m) selectivity on Co-Mo catalysts shifts under different carbon precursors providing the route for (n,m) specific SWCNTs production.