Carbon nanofiber formation on iron group metal loaded on SiO2

• Published in: Diamond and related materials 2006-04, Vol.15 (4-8), p.1080-1084
• Main Authors: YAMADA, Yasuzumi, HOSONO, Yu-Ki, MURAKOSHI, Nobuyuki, HIGASHI, Na-Oki, ICHI-OKA, Hiro-Aki, MIYAKE, Takanori, IKENAGA, Na-Oki, SUZUKI, Toshimitu
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nanoscale materials and structures: fabrication and characterization; Nanotubes; Physics; Theory and models of film growth
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2005.11.025

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 deg C just before the reaction, and CH4, C2H6 or C2H4 was decomposed at 400 to 650 deg 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 deg 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.