Institute of Chemistry, Chinese Academy of Sciences, 100190 Beijing, P.R. China.
Chemistry. 2012 May 29;18(22):6972-8. doi: 10.1002/chem.201103253. Epub 2012 Apr 13.
A high-yielding exfoliation of graphene at high concentrations in aqueous solutions is critical for both fundamental study and future applications. Herein, we demonstrate the formation of stable aqueous dispersions of pristine graphene by using the surfactant sodium taurodeoxycholate under tip sonication at concentrations of up to 7.1 mg mL(-1). TEM showed that about 8% of the graphene flakes consisted of monolayers and 82% of the flakes consisted of less than five layers. The dispersions were stable regardless of freezing (-20 °C) or heat treatment (80 °C) for 24 h. The concentration could be significantly improved to about 12 mg mL(-1) by vacuum-evaporation of the dispersions at ambient temperature. The as-prepared graphene dispersions were readily cast into conductive films and were also processed to prepare Pt/graphene nanocomposites that were used as highly active electrocatalysts for the oxygen-reduction reaction.
在水溶液中高产率地剥离石墨烯并达到高浓度对于基础研究和未来应用都至关重要。在此，我们通过在高达 7.1 mg mL(-1) 的浓度下使用表面活性剂牛磺脱氧胆酸钠进行尖端超声处理，证明了原始石墨烯在水溶液中的稳定分散体的形成。TEM 显示，约 8%的石墨烯薄片由单层组成，82%的薄片由少于五层组成。无论冷冻（-20°C）还是热处理（80°C）24 小时，分散体都很稳定。通过在环境温度下真空蒸发分散体，浓度可显著提高至约 12 mg mL(-1)。所制备的石墨烯分散体可轻易浇铸成导电薄膜，并且还可加工制备 Pt/石墨烯纳米复合材料，将其用作氧还原反应的高活性电催化剂。
