Influence of a Fe/activated carbon catalyst and reaction parameters on methane decomposition during the synthesis of carbon nanotubes

In our experimental work on carbon nanotubes synthesis, the influence of pre-treatment and reaction temperature conditions over Fe catalyst loaded on low-cost activated carbon (AC) in the catalytic chemical vapor deposition of methane was studied. Catalyst with the metal concentration of 5 mass % calcined at 350 degrees C and reduced at 450 degrees C was effective in CH(4) decomposition giving 98 % conversions. TEM images showed that thin multi-walled carbon nanotubes (MWNTs) with the average internal diameter of similar to 8 nm and the wall thickness of similar to 2.5 nm were obtained over unreduced Fe/AC catalyst at the reaction temperature of 850 degrees C. On the other hand, broader filamentous nanostructures with the diameter of similar to 22 nm and the wall thickness of similar to 3.72 nm were observed over reduced catalyst. (C) 2010 Institute of Chemistry, Slovak Academy of Sciences