TY - JOUR
T1 - Synthesis of carbon nanotubes on carbon fibers by means of two-step thermochemical vapor deposition
AU - Sonoyama, Nozomu
AU - Ohshita, Mikio
AU - Nijubu, Akio
AU - Nishikawa, Hidetoshi
AU - Yanase, Hironori
AU - Hayashi, Jun ichiro
AU - Chiba, Tadatoshi
N1 - Funding Information:
A main portion of this work was part of a research project aimed at developing polymer electrolyte fuel cells and was financed by The New Energy and Industrial Technology Development Organization (NEDO), Japan. Nozomu Sonoyama also gratefully acknowledges financial support from The Thermal and Electric Energy Technology Foundation (TEET), Japan.
PY - 2006/8
Y1 - 2006/8
N2 - The present study aimed at development of a method for synthesizing multi-walled carbon nanotubes (CNTs) on carbon paper substrates (CP) at densities as high as those so far reported for CNTs formed on quartz substrates. Applying conditions optimized for CNTs synthesis on quartz substrates, in which CP was heated at 1073 K, being placed parallel to the flow of m-xylene/ferrocene vapor, resulted in formation of extremely few deposits on CP. Forced vapor flow through the CP greatly improved the frequency and homogeneity of deposition of the Fe-bearing nanoparticles, but these became encapsulated by carbon and deactivated. The addition of H2S to the vapor further enhanced nanoparticle deposition. Moreover, it enabled the subsequent formation of CNTs at densities as high as 2-6 × 109 cm-2. In order to realize such high population densities, it was found essential to perform CVD in a two-stage sequence commencing with nanoparticles deposition at 1073 K followed by the formation and growth of CNTs at 1273 K, with the H2S concentration in the vapor phase optimized throughout within a range of 0.014-0.034 vol%.
AB - The present study aimed at development of a method for synthesizing multi-walled carbon nanotubes (CNTs) on carbon paper substrates (CP) at densities as high as those so far reported for CNTs formed on quartz substrates. Applying conditions optimized for CNTs synthesis on quartz substrates, in which CP was heated at 1073 K, being placed parallel to the flow of m-xylene/ferrocene vapor, resulted in formation of extremely few deposits on CP. Forced vapor flow through the CP greatly improved the frequency and homogeneity of deposition of the Fe-bearing nanoparticles, but these became encapsulated by carbon and deactivated. The addition of H2S to the vapor further enhanced nanoparticle deposition. Moreover, it enabled the subsequent formation of CNTs at densities as high as 2-6 × 109 cm-2. In order to realize such high population densities, it was found essential to perform CVD in a two-stage sequence commencing with nanoparticles deposition at 1073 K followed by the formation and growth of CNTs at 1273 K, with the H2S concentration in the vapor phase optimized throughout within a range of 0.014-0.034 vol%.
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U2 - 10.1016/j.carbon.2005.12.039
DO - 10.1016/j.carbon.2005.12.039
M3 - Article
AN - SCOPUS:33646461128
SN - 0008-6223
VL - 44
SP - 1754
EP - 1761
JO - Carbon
JF - Carbon
IS - 9
ER -