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Size Control of Metal Nanoparticle Catalysts for the Gas-Phase Synthesis of Single-Walled Carbon Nanotubes

2005; American Chemical Society; Volume: 109; Issue: 21 Linguagem: Inglês

10.1021/jp044200z

1520-6106

Takeshi Saito, Satoshi Ohshima, Wei-Chun Xu, Hiroki Ago, Motoo Yumura, Sumio Iijima,

Fullerene Chemistry and Applications

Nanoparticle catalysts are essential and indispensable for all syntheses of single-walled carbon nanotubes (SWCNTs). We have prepared size-controlled Co, Co−Mo, and Fe−Mo nanoparticles by the reversed micelle method as the catalysts for the gas-phase pyrolytic synthesis of SWCNTs. From the investigation of the relation between the sizes of the nanoparticles and the alkyl-chain lengths of the cationic surfactants, dialkyldimethylammonium bromides, it has been found that the alkyl groups of the surfactants could play a role in controlling the sizes of the nanoparticles and that the alkyl chain of the surfactant should be preferably less than 10 carbon atoms at most to prepare smaller-size nanoparticles with a narrow size distribution. The reduction of the particle size increases the number of nanoparticles in the colloidal solution and leads to a higher yield of SWCNTs.