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Carbon nanostructures produced by pyrolysis under high pressure inside a nanosize silica matrix
Author(s) -
Villanueva Antonio E. L.,
Balzaretti Naira M.,
Jornada Joao A. H.
Publication year - 2012
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.3150
Subject(s) - pyrolysis , raman spectroscopy , carbon fibers , materials science , nanostructure , chemical engineering , fumed silica , graphene , transmission electron microscopy , dispersion (optics) , nanoparticle , nanotechnology , composite material , composite number , physics , optics , engineering
In this work, the pyrolysis under high pressure of hydrocarbons dispersed inside a nanosized silica matrix (Aerosil) was investigated. The samples consisted of hydrophobic nanometric silica powder terminated by methyl groups with carbon contents ranging from 0.7 to 4 wt%. The pyrolysis was carried out in the temperature range from 1000 to 1600 °C under high pressure (1.25 up to 7.7 GPa) to keep the two‐dimensional distribution of carbon atoms originally at the silica grain boundaries. Evidences from Raman spectroscopy and transmission electron microscopy suggested that the resulting carbon nanostructures were actually graphene‐like nanoflakes. The size of the nanostructures calculated from the I D / I G ratio increased from 6 to 30 nm for processing temperatures increasing from 1000 to 1600 °C under pressure, respectively. The results revealed that the very good dispersion of the methyl groups inside the nanosize silica matrix, and the confinement under high pressure during the pyrolysis, played both a relevant role in the resulting carbon nanostructures. Copyright © 2012 John Wiley & Sons, Ltd.