Summary: © 2009 Macmillan Publishers Limited. All rights reserved.
New insights into the structure and reduction of
, Lawrence B. Alemany1
, Lijie Ci2
and Pulickel M. Ajayan1,2
Graphite oxide is one of the main precursors of graphene-based materials, which are highly promising for various
technological applications because of their unusual electronic properties. Although epoxy and hydroxyl groups are widely
accepted as its main functionalities, the complete structure of graphite oxide has remained elusive. By interpreting
spectroscopic data in the context of the major functional groups believed to be present in graphite oxide, we now show
evidence for the presence of five- and six-membered-ring lactols. On the basis of this chemical composition, we devised a
complete reduction process through chemical conversion by sodium borohydride and sulfuric acid treatment, followed by
thermal annealing. Only small amounts of impurities are present in the final product (less than 0.5 wt% of sulfur and
nitrogen, compared with about 3 wt% with other chemical reductions). This method is particularly effective in the
restoration of the p-conjugated structure, and leads to highly soluble and conductive graphene materials.
raphene--a single layer of sp2
-hybridized carbon atoms