Patent ID: 6913789

Claim:
A method for producing single-wall carbon nanotubes, comprising: (a) providing a supercritical fluid catalyst stream comprising (i) a supercritical fluid and (ii) a catalyst precursor selected from the group consisting of multi-metallic catalyst precursors, mono-metallic catalyst precursors, and mixtures thereof that are dissolved, suspended, or both in the fluid, each multi-metallic catalyst precursor comprising at least two atoms, and each mono-metallic catalyst precursor comprising one atom, of at least one transition metal selected from the group consisting of Group VIb elements and Group VIIIb elements, wherein the supercritical fluid catalyst stream is at a temperature below the decomposition temperature of the catalyst precursor; (b) providing a carbon feedstock gas stream at a temperature above the minimum single-wall carbon nanotube formation initiation temperature; and (c) mixing the carbon feedstock gas stream with the supercritical fluid catalyst stream to form a mixed gas stream, wherein the carbon feedstock gas stream heats the mixed gas stream and wherein without the need for additional heating (i) the catalyst precursor in the mixed gas stream will reach a temperature above the decomposition temperature of the catalyst precursor, (ii) the temperature of the mixed gas stream is sufficient to promote the initiation or growth of catalyst clusters, and (iii) the temperature of the mixed gas stream is sufficient to promote the initiation and growth of single-wall carbon nanotubes on the catalyst clusters and to form the single-wall carbon nanotubes in the mixed gas stream.