Department of Chemistry, Rice University, Houston, Texas 77005, USA.
Nat Chem. 2009 Aug;1(5):403-8. doi: 10.1038/nchem.281. Epub 2009 Jul 5.
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.
氧化石墨是基于石墨烯的材料的主要前体之一，由于其独特的电子特性，在各种技术应用中具有广阔的前景。尽管环氧基和羟基被广泛认为是其主要官能团，但氧化石墨的完整结构仍然难以捉摸。通过在被认为存在于氧化石墨中的主要官能团的背景下解释光谱数据，我们现在证明了五元环和六元环内缩醛的存在。基于这种化学成分，我们通过硼氢化钠和硫酸处理的化学转化设计了一个完整的还原过程，然后进行热退火。最终产物中只存在少量杂质（与其他化学还原方法相比，硫和氮的含量低于 0.5wt%，而约为 3wt%）。这种方法在恢复π共轭结构方面特别有效，导致高可溶性和导电性的石墨烯材料。
