Low temperature synthesis of iron containing carbon nanoparticles in critical carbon dioxide
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We develop a low temperature, organic solvent-free method of producing iron containing carbon (Fe@C) nanoparticles. We show that Fe@C nanoparticles are self-assembled by mixing ferrocene with sub-critical (25.0 °C), near-critical (31.0 °C) and super-critical (41.0 °C) carbon dioxide and irradiating the solutions with UV laser of 266-nm wavelength. The diameter of the iron particles varies from 1 to 100 nm, whereas that of Fe@C particles ranges from 200 nm to 1 μm. Bamboo-shaped structures are also formed by iron particles and carbon layers. There is no appreciable effect of the temperature on the quantity and diameter distributions of the particles produced. The Fe@C nanoparticles show soft ferromagnetic characteristics. Iron particles are crystallised, composed of bcc and fcc lattice structures, and the carbon shells are graphitised after irradiation of electron beams.
KeywordsNanoparticles Carbon Iron Ferrocene Critical carbon dioxide UV laser Composite nanomaterials
Part of this study has been supported by a Grant for the High-Tech Research Centres organised by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, since 2006. T. Fukuda would like to thank MEXT for their financial support.
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