Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 98: Graphene: Intercalation

O 98.6: Vortrag

Freitag, 20. März 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).