Graphitic Structures by Design

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• 作者：Jonathan Phillips ; Toshi Shiina ; Martin Nemer ; Kelvin Lester
• 刊名：Langmuir
• 出版年：2006
• 出版时间：November 7, 2006
• 年：2006
• 卷：22
• 期：23
• 页码：9694 - 9703
• 全文大小：1506K
• 年卷期：v.22,no.23(November 7, 2006)
• ISSN：1520-5827

文摘

It is shown that self-supporting graphitic structures of specific shape can be grown in a variety of forms, fromnanoscale to macroscale, on metal templates, in a fuel-rich mixture of ethylene and oxygen at temperatures between750 and 900 K. The evidence presented suggests graphite can be grown in any shape created from catalytic metals(e.g., Ni) under the proper conditions of temperature and gas composition. Structures produced include macroscalebodies, centimeters in dimension, composed of micrometer-scale graphite elements such as graphite "foam" andregular graphite "lattices". Nanoscale hollow graphite spheres were also produced. The production rate in the apparatusemployed was roughly shown to be 1 layer/s and was steady with time over several hours. The process of producingself-supporting bodies generally produces hollow graphite structures, as the underlying metal template must be removedby acid following the completion of graphite growth. The process is believed to be possible only in an environment,such as combustion, in which a high concentration of particular radical species is present in the vicinity of the templatesurface. The following process is postulated: (i) a single layer of graphite is formed from gas-phase radicals by thecatalytic action of the metal template, (ii) additional graphite growth is "autocatalytic" and occurs via the decompositionof radicals on the surface and the incorporation of "free" carbon atoms, or other radical fragments, into "edge sites"on the graphite surface.