this problem. It can be inferred that the gas-flow fields, associated
heat, and mass transfer in the vertical CVD reactor were more
complex than in the horizontal CVD reactor.
We speculated that the appearance of this octopus-tentacle-like
structure was due to the following mechanism: some straight CNTs
were preformed at the 700 C zone in the chamber; when they fell
into the lower zones with lower temperatures, the decomposed
carbon atoms at 650 C or 600 C deposited on the surface of the
preformed CNTs, thus forming this special octopus-tentacle-like
structure. We have yet to determine the optimal application for
this carbon structure. However, the hollow center and the rough
and wavy wall surfaces of the octopus-tentacle-like structure can
provide a specific surface area substantially larger than those of
CNTs and CNCs, which suggests various potential applications such
as hydrogen storage media, microwave absorbers, microsensors,
and catalyst supports.
4. Conclusion
In this work, we used a poly(styrene-co- NIPAAm)/pd catalysts
and the SPCVD method with a vertical furnace to synthesize
nanocarbonaceous materials. By adjusting the growth temperature,
we could control the morphology and structure of the nanocarbon
products. Our results indicated that a higher temperature (700 or
800 C) was more conducive to the formation of CNTs, while a
lower temperature (600 C) was more favorable for the synthesis of
CNCs. The growth rate of nanocarbonaceous materials increased
with the increase of the flow rate of the carbon source gas. Moreover,
separately setting the temperatures of both the vertical CVD