GAS-PHASE NUCLEATION AND GROWTH OF SINGLE-WALL CARBON NANOTUBES FROM HIGH PRESSURE CO

摘要

The present invention discloses the process of supplying high pressure (e.g.,30 atmospheres) CO that has been preheated (e.g., toabout 1000 °C) and a catalyst precursor gas (e.g., Fe(CO)5) in CO thatis kept below the catalyst precursor decomposition temperature toa mixing zone. In this mixing zone, the catalyst precursor is rapidly heatedto a temperature that results in (1) precursor decomposition,(2) formation of active catalyst metal atom clusters of the appropriate size,and (3) favorable growth of SWNTs on the catalyst clusters.Preferably a catalyst cluster nucleation agency is employed to enable rapidreaction of the catalyst precursor gas to form many small, activecatalyst particles instead of a few large, inactive ones. Such nucleationagencies can include auxiliary metal precursors that cluster morerapidly than the primary catalyst, or through provision of additional energyinputs (e.g., from a pulsed or CW laser) directed precisely atthe region where cluster formation is desired. Under these conditions SWNTsnucleate and grow according to the Boudouard reaction. TheSWNTs thus formed may be recovered directly or passed through a growth andannealing zone maintained at an elevated temperature (e.g.,1000 °C) in which tubes may continue to grow and coalesce into ropes.