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Synthesis of Carbon Spheres/Tubes Using a Mixed-Valent Oxide-Catalytic Carbonization Process

Published online by Cambridge University Press:  10 February 2011

Z. C. Kang  and
Z. L. Wang
Z. C. Kang
Affiliation:
School of Material Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332–0245, USA.
Z. L. Wang
Affiliation:
School of Material Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332–0245, USA. e-mail: zhong.wang@mse.gatech.edu
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Abstract

A mixed-valent oxide-catalytic carbonization (MVOCC) process is described for synthesizing monodispersed carbon spheres (or tubes) in macroscopic quantities at low cost. The technique uses natural gas and reusable catalysts and produces no environmental waste or pollution. The product is controlled to be either all of spheres (∼ 210 nm) or all of tubes with high purity (> 95 %). In spherical form, the product is solid and comprised of layered graphitic flakes containing paired pentagonal-heptagonal carbon-rings. In spiral tube form, the product is composed of twisted graphitic helix layers containing spherical nodes. A growth mechanism has been proposed, in which the pairing of pentagonal and heptagonal carbon-rings plays an important role. It is concluded that a change in fraction and nucleation rates of pentagonal, hexagonal and heptagonal carbon-rings results in the growth of different geometrical shapes. The success of using mixed-valence metal oxides as catalysts has opened a new field in catalysis research and applications.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 454: Symposium S – Advanced Catalytic Materials–1996 , 1996 , 15
Copyright
Copyright © Materials Research Society 1997

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References

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