Synthesis of very dense carbon nanotube bundles using silica supported metal catalyst

Films composed of iron nanoparticles dispersed in silica were prepared starting from the mixture of tetraethoxysilane(TEOS), iron nitrate Fe(NO/sub 3/)/sub 3//spl middot/9H/sub 2/O, and ethanol using the solgel method. As it turned out, the silica supported iron nanoparticles were very efficient catalysts for carbon nanotube growth, and therefore, very long and dense bundles of multiwall carbon nanotubes were synthesized; the nanotube density was so high that nanotubes were appeared aligned in spite of the curliness of the individual nanotubes.