ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 4, pp. 603!608. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + I.I. Obraztsova, N.K. Eremenko, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 4, pp. 565!570.
OF SYSTEMS AND PROCESSES
Physicochemical Modification of Nanodiamonds
I. I. Obraztsova and N. K. Eremenko
Kemerovo Branch, Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch,
Russian Academy of Sciences, Kemerovo, Russia
Received June 18, 2007
Abstract-Thermal modification of nanodiamonds in the atmosphere of argon and hydrogen and their
chemical modification with oleum and chlorine at different temperatures were studied. The effect of the mod-
ification conditions on the catalytic activity of palladium catalysts supported by nanodiamonds in the reaction
of nitrobenzene hydrogenation and on the adsorption properties of nanodiamonds with respect to benzene,
chloroform, and water was analysed.
The increased scientific and practical interest in
synthesis and study of substances in the nanostate is
due to the fact that they possess new functional prop-
erties because the size of nanoparticles is in the range
m, which is comparable with that of mol-
ecules. An object of this kind are nanodiamonds (ND)
produced by detonation synthesis with explosives
having a negative oxygen balance in a nonoxidative
medium, which yields a carbon stock containing
the diamond fraction.
The recovery and purification of ND or, as they
are also named, utradispersed diamonds (UDD) can
be divided into the gas- and liquid-phase methods.
Oxygen and air are used in the first case, and oxidiz-
ing mixtures (H
, etc.), in the second [13 4]. In the pro-
cess, new functional groups are added to those already
present on the UDD surface, depending on the recov-
The presence of functional groups with various
chemical compositions on the surface of ND prede-
termines their widely diverse and unique properties.
Therefore, methods used to modify ND may be of key
importance for various applications.
At present, nanodiamonds are used in electrodepos-
ited metal3diamond coatings, antifriction additives,
various lubricants, lubricating-cooling fluids for phys-
ical modification of ferrolacquer coatings of magnetic
tapes and disks, as composite materials in polymeric
films and membranes, in various rubbers, and as car-
riers of biological and medicinal preparations [5, 6].
Development of methods for controlling the chem-
ical composition of the nanodiamond surface by vary-
ing the amount and nature of functional groups opens
the way to their modification for creating new types
of ND, including those with a multifunctional surface
In this study, thermal and chemical modification
of nanodiamonds was carried out in order to expand
the application fields of UDD.
ND recovered from a detonation diamond stock
by the previously developed technique [4, 7] and
additionally dried in air at 150oC was used in
ND were thermally treated for 4 h in a quartz re-
actor similar to that used for determining carbon and
hydrogen in organic compounds . Argon or hydro-
gen served as a carrier gas. Prior to an experiment,
the system was purged with carrier gas for 10 min.
The released water was absorbed with anhydrone and
its amount was found from the increase in the mass of
this drying agent. Carbon dioxide was absorbed with
solution of a known concentration (with
subsequent titration with 0.2 N HCl). The amount
of the released carbon monoxide was found by its ab-
sorption with an acetone solution of palladium(II),
with metallic palladium recovered and the unreacted
gravimetrically determined with dimethylgly-