Stability of fullerenes under hydrothermal conditions
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Stability of fullerenes under hydrothermal conditions Wojciech L. Suchaneka) and Masahiro Yoshimura Center for Materials Design, Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 Japan
Yury G. Gogotsi Department of Mechanical Engineering, M/C 251, University of Illinois at Chicago, Chicago, Illinois 60607-7022 (Received 28 July 1998; accepted 15 September 1998)
Stability of fullerenes C60 under hydrothermal conditions (200–800 ±C, 100 MPa, 20 min–168 h) has been investigated. The reaction products have been characterized by Raman spectroscopy and x-ray diffraction. The fullerenes were stable up to 500 ±C, but they decomposed immediately at 800 ±C into amorphous carbon. In the transition region between 600 and 750 ±C, longer times and higher temperatures of the hydrothermal treatment favored decomposition of C60 with the formation of amorphous carbon. Addition of nickel to the C60 –H2 O system neither suppressed hydrothermal decomposition of C60 nor induced formation of other phases, except of the amorphous carbon.
Fullerenes and fullerene-related materials in recent years have attracted great interest from researchers all over the world. Since their first discovery in 1985 by Kroto et al.,1 the number of papers related to these materials has increased rapidly.2 Fullerenes and related carbon structures have been the subject of books and review articles.3– 9 Such an interest in this field is due to multiple potential applications of the new carbon allotropes. Applications of fullerenes include energy production (electrodes in batteries, hydrogen storage media),6 superconductors (when doped with alkali metals), catalysts, photoconductors, optical limiters, and diamond precursors.5,6 Additionally, there is a possibility of fabrication of an enormous number of new fullerenebased compounds with still unknown properties and applications because various metal atoms can substitute carbon atoms10 or be imprisoned within the fullerene cage,10 and also multiple functional groups can be attached to the carbon atoms in the fullerene structure.6 Recently, interactions between fullerenes and water in a broad range of temperatures and pressures have attracted the attention of researchers. It has been demonstrated that hydrothermal pretreatment of the fullerene soot increases efficiency of the fullerene extraction.11,12 Purification of fullerene nanotubes using the hydrothermal treatment13 or via other routes using aqueous solutions14 has been successfully accomplished. Aqueous electrochemistry of fullerene films/electrodes has been recently intensively investigated.15,16 In addition, research on aqueous chemistry of soluble in water-
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Present address: Universite Pierre et Marie Curie, Chimie de la Matiere Condensee, 4, place Jussieu (T54–E5), 75252 Paris, France. J. Mater. Res., Vol. 14, No. 2, Feb 1999
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functionalized fullerenes17 has been pursued with a view tow
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