II International Symposium on Carbon for Catalysis ABSTRACTS

PP-I-37
As one can see in the table, XRD shows that graphite anodic oxidation in the above
mentioned electrolyte does not allow to obtain graphite intercalation compound. But the value
of d i increased from 3.35 Å for the initial graphite up to 3.36-3.38 Å for synthesized
compounds. Probably, the anodic oxidation and hydrolysis occurs at the same time and the
final product is expandable graphite. This material is able to exfoliate at quick heating with
the formation of exfoliated graphite (EG). The presence of nickel compounds in the
expandable graphite was confirmed by qualitative analysis.
The expandable graphite samples were subjected to thermal shock at 250 and 900 o C.
Exfoliated graphite is known to be obtained at 900 o C [3]. It is necessary to note that
synthesized samples are able to exfoliate at 250 o C, the bulk density is 1 – 60 g/l and depends
on the way of synthesis. The bulk density of EG obtained at 900 o C is 1 – 18 g/l. Thus, anodic
oxidation of natural graphite under such conditions permits to obtain very light material. The
specific area of the exfoliated graphite is 20 – 110 m 2 /g.
The content of nickel oxide in the exfoliated graphite was determined quantitatively by
incineration of EG in the air flow at 900 o C for several hours. XRD analysis of the rest
confirmed single phase of NiO. The quantity of nickel oxide in the exfoliated graphite strictly
depends on the way of synthesis.
The structural peculiarities of the expandable and exfoliated graphite were investigated
with the use of scanning electron microscopy. It was shown that finely-dispersed inclusions of
nickel oxide in exfoliated graphite are distributed not homogeneously, and accumulation areas
can be observed.
Thus, anodic oxidation of natural graphite followed by thermal treatment allows to obtain
carbonaceous materials doped by nickel oxide. These materials are believed to be used as
catalysts in different organic reactions.
References
1 Nicholls J.T., Speck J.S., Dresselhaus G. // Physical Review B. 1989. V.39. N.14.
P.10047-10055.
2 Touzain P., N’Guessan G.K., Bonnin D., Kaiser P., Chouteau G. // Synthetic metals.
1996. V.79. P.241-251.
3 Celzard A., Mareche J.F., Furdin G. // Progress in Material Science. 2005. V.50.
P.93-179.
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