高导电水溶性石墨烯的制备及其分散机制的研究

Graphene oxide has attracted extensive interests due to its good dispersibility in water, and is usually used as a precursor for reduced graphene oxide with lower oxygen content and functional composite materials. However, reduced graphene oxide is easily aggregated. It becomes a research focus to enhance the water solubility of graphene with low oxygen content. Recent studies indicate that the direct introduction of a small number of oxygen on the two-dimensional planes enables graphene to possess good dispersibility in water (low-oxygen graphene). Therefore, it is necessary to investigate the difference between low-oxygen graphene and reduced graghene oxide, and the least oxygen content for the possibility to maintain good dispersibility of graphene and enhance its conductivity. Based on the reported methods to prepare graphene oxide, the project will control the oxidation process of graphite, and then adopt different reduction technologies to selectively remove oxygen-containing functional groups step by step. Oxygen doped graphene with different architectural features will be fabricated. Subsequently, the dispersibility of the oxygen doped graphene will be systemically examined to establish the dispersion mechanism and develop a new method to prepare water-soluble graphene with high conductivity. In addition, we will investigate the connection between the conductivity and capacitance of oxygen doped graphene, realizing the performance optimization. The success of the project will facilitate the deep understanding and extensive applications of graphene.

氧化石墨烯由于出色的水溶性已被广泛研究，常作为前驱体规模化制备较低氧含量还原氧化石墨烯及其复合功能材料。但是，还原氧化石墨烯容易发生团聚。如何提高低氧含量石墨烯的水溶性成为研究热点。最近研究表明石墨烯二维平面上只需直接引入少量的氧就能使其在水中很好地分散（低氧石墨烯）。然而，低氧石墨烯与还原氧化石墨烯之间的差异性，以及氧掺杂石墨烯的氧含量减小到何等程度既能不牺牲其分散浓度又能提高自身的导电率有待解决。本项目拟在现有氧化石墨烯制备方法的基础上控制石墨氧化进程，选用不同的还原技术逐步、选择性地去除各种氧官能团，制备出具有不同结构特征的氧掺杂石墨烯，考察它们的分散性，建立氧掺杂石墨烯的分散机制，提出制备高导电水溶性石墨烯的新方法；研究氧掺杂石墨烯导电率与其电容量之间的关系，实现性能最优化。本项目的成功实施在石墨烯化学性质认识方面具有重要的学术意义，并为石墨烯广泛的应用创造有利条件。

氧化石墨烯由于出色的水溶性已被广泛研究，常作为前驱体规模化制备较低氧含量还原氧化石墨烯及其复合功能材料。但是，还原氧化石墨烯容易发生团聚。如何提高低氧含量石墨烯的水溶性成为研究热点。最近研究表明石墨烯二维平面上只需直接引入少量的氧就能使其在水中很好地分散。然而，氧掺杂石墨烯的分散机制尚未清楚，严重阻碍了高导电水溶性石墨烯的开发及应用。本项目在现有氧化石墨烯（GO）制备方法的基础上控制石墨氧化进程，选用不同的还原技术去除各种氧官能团，发现以GO为前驱体制得的导电石墨烯水溶性差且不稳定；利用GO出色的水溶性开发了GO包覆的介孔二氧化硅，提高对高浓度贵金属离子的吸附性能；系统研究了无缺陷石墨烯的分散规律，发现其剥离规律与分散规律不同；提出了醇辅助提高无缺陷石墨烯在水中分散性的方法；揭示了石墨烯、二硫化钼等二维材料两亲特性；建立了石墨烯基界面材料宏观的润湿性质与其微观的分散性之间的关联性，发展了在溶质传质领域中的应用。本项目的预期成果将为石墨烯等原子厚度二维材料的分散性等本征润湿性质的研究提供理论依据和实验指导，促进它们分散体系的开发，拓展与润湿相关的界面应用。