Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 98: Graphene: Intercalation
O 98.6: Talk
Friday, March 20, 2015, 11:45–12:00, MA 041
Oxidation of sulfuric acid intercalated graphite: the role of sulfuric acid and permanganate ions — •Steffen Seiler and Bernd Meyer — Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, FAU Erlangen-Nürnberg
Wet-chemical exfoliation of graphite via Hummers’ method [1,2]
is a promising route for large-scale graphene production. This
solution-based process is carried out in concentrated sulfuric acid
and involves several steps: first, graphite is converted into a
sulfuric acid–graphite intercalation compound (GIC), then the GIC
is transformed into oxidized graphite, graphene oxide (GO) layers
are separated in solution by hydrolysis reactions, and finally the
GO layers are reduced to graphene [3].
To obtain atomistic insights into the mechanisms of the chemical
reactions in liquid sulfuric acid within the confined space between
graphene layers we performed Car-Parrinello molecular dynamics
(CP-MD) simulations.
By changing the coverage of hydroxy and epoxy groups their stabilizing
effect on the attack of sulfuric acid (solvent) and KMnO4
(oxidizing agent) molecules was investigated. Furthermore, different
carbon atoms on the partly oxidized graphene sheets were attacked to
elucidate the most reactive sites.
[1] W. S. Hummers, J. Am. Chem. Soc. 80, 1339
(1958).
[2] D. C. Marcano et al., ACS Nano 4, 4806
(2010).
[3] A. M. Dimiev and J. M. Tour, ACS Nano 8, 3060
(2014).