학술논문
X-ray diffraction and Mo¨ssbauer characterization of an Fe/SiO[sub 2] catalyst for the synthesis of carbon nanotubes.
Document Type
Article
Source
Subject
*CATALYSTS
*IRON
*SILICA
*NANOTUBES
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*
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Language
ISSN
0021-8979
Abstract
A catalyst powder was prepared by adsorption precipitation of iron acetate on a SiO[sub 2] support at a controlled pH. The selective reduction of this powder in a N[sub 2]/C[sub 2]H[sub 2] atmosphere at 700 °C generates multiwall carbon nanotubes. The study by x-ray diffraction and Mössbauer spectroscopy of the catalyst and reduced powders reveals that hematite particles with a 8-20 nm size range are involved in the formation of these carbon nanotubes and end up as Fe[sub 3]C after the catalysis process. Moreover, coalescence upon reduction produces large particles responsible for the formation of a minor proportion of large tubes of the order of 100 nm in diameter. [ABSTRACT FROM AUTHOR]