Abstract
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 π-conjugated structure, and leads to highly soluble and conductive graphene materials.
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Acknowledgements
The authors (P.M.A., L.C., W.G.) acknowledge the support from the Interconnect Focus Center, one of five research centers funded under the Focus Center Research Program, a Semiconductor Research Corporation program. The authors also thank James M. Tour, Ashley Leonard, and Sun Zhengzong for helpful discussions and instrumental support.
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W.G. and L.B.A. designed and performed the experiments and analysed the data. L.B.A. was responsible for all the NMR experiments and analysis. L.C. contributed materials, analysis tools and prepared the graphical abstract. W.G., L.B.A. and P.M.A. co-wrote the paper. P.M.A. was responsible for project planning. Correspondence and requests for materials should be addressed to P.M.A.
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Gao, W., Alemany, L., Ci, L. et al. New insights into the structure and reduction of graphite oxide. Nature Chem 1, 403–408 (2009). https://doi.org/10.1038/nchem.281
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DOI: https://doi.org/10.1038/nchem.281
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