Flame synthesis of carbon nanotubes using catalyst particles prepared by laser ablation was studied. A greater yield of nanofibers of greater length were produced with the CO/C2H2 based gas mixture than with C2H2 alone. The reactivity of nickel towards C2H2 (at the same concentration) in the absence of CO increased, where fewer nanofibers, of shorter lengths were produced (along with encapsulated particles). Ultrasmall Ni particles (< 4 nm) might not be particularly active towards catalyzing C2H2 dissociation. Fe exhibited selective reactivity towards CO. Moreover, the absence of nanofibers of MWNT suggested a decline in reactivity with increasing particle size for Fe nanoparticles, in contrast to nickel. In a metal nanoparticle, the density of electronic states is finite and the traditional conduction and valence bands are absent due to the small number of constituent atoms.
|Original language||English (US)|
|Number of pages||2|
|Journal||ACS Division of Fuel Chemistry, Preprints|
|State||Published - Sep 1 2004|
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