The name is absent

arc, IOO A of current passes between them, creating a plasma which provides a
nucleating environment for CNTs. To this day, arc-discharge is still a preferred
method for ultra-high-quality CNTs if there is little concern about length, though
other methods have since surpassed it in producing much larger quantities.

In 1993, José-Yacamân et al. reported the first use of CVD for the expressed
purpose of synthesizing CNTs [13]. The CVD process generally involves the use of a
hydrocarbon gas which decomposes in a high temperature environment, producing
the feedstock carbon for CNT synthesis. When placed in a sufficient but not
excessive temperature environment (generally ~700 - 900 ^oC), catalyst particles of
certain transition metals will begin to consume any available carbon and initiate the
growth of CNTs. In this last-referenced work [13], acetylene was passed over a
substrate covered with iron particles in a 700 ⁰C atmosphere, resulting in the
growth of CNTs up to 50 μm in-length. Shortly after, Endo et al. were able to initiate
the use of a vapor-phase catalyst to synthesize pyrolized CNT structures by adapting
a procedure similar to what is used to create vapor-grown carbon nanofibers
(VGCNFs) [14]. By passing benzene over a carbon block in a hydrogen-rich
environment at 1000 ⁰C, highly-graphitic CNTs and CNT-Iike structures were
generated. CVD is also responsible for the high-pressure CO (HiPCO) growth
method developed by Nikolaev et al. in 1999, which has allowed for the large-scale
production ofSWNTs [15]. Due to its relative ease, there have been many variations
on the CVD synthesis of CNTs which have brought it to prominence as a simple, yet
effective method to produce large quantities of CNTs.

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