Carbon nanofiber formation on iron group metal loaded on SiO₂

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• 作者：Yasuzumi Yamada ; Yu-ki Hosono ; Nobuyuki Murakoshi ; Na-oki Higashi ; Hiro-aki Ichi-oka ; Takanori Miyake ; Na-oki Ikenaga and Toshimitu Suzuki
• 关键词：Nanotube ; Chemical vapor deposition ; Catalytic processes ; Nanotechnology
• 刊名：Diamond and Related Materials
• 出版年：2006
• 出版时间：April-August 2006
• 年：2006
• 卷：15
• 期：4-8
• 页码：1080-1084
• 全文大小：371 K

文摘

Systematic and quantitative approaches for carbon nanofiber (CNF) synthesis with catalytic chemical vapor deposition (CCVD) method were performed. Ni, Co and Fe metals were impregnated from aqueous solutions of respective acetate onto spherical SiO₂. The catalyst was reduced at a temperature range from 500 to 700 °C just before the reaction, and CH₄, C₂H₆ or C₂H₄ was decomposed at 400 to 650 °C. On Co and Ni loaded catalyst the amount of CNF increased with an increase in the reaction temperature and showed maxima, irrespective of hydrocarbon sources. However, at a reaction temperature of 600 or 700 °C, on Co and Ni no CNF was obtained.

Dispersion of Co metals on SiO₂ was greatly affected by H₂ reduction temperature. At the higher reduction temperature, the amount of CNFs decreased on Co/SiO₂ and CNF formation behavior was significantly affected by the hydrocarbon source, but on Ni/SiO₂ the effects of reduction temperatures were not significant on the amounts of CNF. With all the hydrocarbon sources, the amounts of CNFs obtained at optimal conditions were as follows: Ni > Co Fe. TEM observation of the catalysts and CNFs grown under different conditions clarified CNF growth process, for the iron group metal loaded on SiO₂.