NANOSYSTEMS: PHYSICS, CHEMISTRY, MATHEMATICS, 2014, 5 (5), P. 659-676
NANOSCALE REDUCED-GRAPHENE-OXIDE ORIGIN OF SHUNGITE IN LIGHT OF NEUTRON SCATTERING
E. F. Sheka – Faculty of Physics, Mathematics and Natural Sciences, Peoples’ Friendship University of Russia, Moscow, Russia; sheka@icp.ac.ru
N. N. Rozhkova – Institute of Geology, Karelian Research Centre RAS, Petrozavodsk, Russia; rozhkova@krc.karelia.ru
K. Ho lderna-Natkaniec – Faculty of Physics, Adam Mickiewicz University, Poznan, Poland
I Natkaniec – Faculty of Physics, Adam Mickiewicz University, Poznan, Poland; Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russia; inat@jinr.ru
New concept of shungite carbon exhibits this raw material as a multi-level fractal structure of nanosize fragments of reduced graphene oxide (rGO) (Int. J. Smart Nano Mat. 1, 1, 2014). The natural rGO deposits turn out to be quite challenging for the current graphene technology. Once consistent with all the block of the available geological and physicochemical data obtained during the last few decades, the concept nonetheless needs a direct con rmation in terms of the current graphene science. The rst such acknowledgement has been received just recently when studying photoluminescence (PL) of shungite dispersions (JETP 118, 735, 2014). A close similarity of PL spectra of aqueous dispersion of shungite and those of synthetic graphene quantum dots of the rGO origin has been established. The current paper presents the next direct con rmation provided with neutron scattering. Elastic neutron di raction and inelastic neutron scattering have left no doubts concerning both graphene-like con guration and chemical composition of basic structural elements of shungite attributing the latter to rGO nanosize sheets with an average ~6:0.1:2 (C:O:H) atomic content ratio per one benzenoid unit. The experimental data are supplemented with quantum-chemical calculations that allowed suggesting a clear vision of the shungite structure at its fi rst fractal levels.
Keywords: shungite; natural nanoscale reduced graphene oxide; multi-stage reduction of graphene oxide; retained water; elastic and inelastic neutron scattering; quantum chemical calculations.
PACS 61.05.fg, 61.46.+w, 63.22. m, 81.05.Uw