氧化石墨烯的制备和定性定量分析

Qualitative and Quantitative Analysis of Graphene Oxides by UV Spectroscopy

以鳞片石墨为原料,采用硫酸和高锰酸钾,通过化学插层氧化-破碎方法制备了氧化石墨烯(GO),通过扫描电镜(SEM)、激光粒度分析、红外光谱(FT-IR)、紫外-可见光谱(UV-vis)和原子力显微镜(AFM)等测试手段对所制备的氧化石墨烯进行了分析和表征。结果发现230 nm附近的紫外可见光谱可以把氧化石墨烯与氧化石墨进行区分。结果表明紫外光谱可对氧化石墨烯溶液进行定性分析和定量分析。通过这一方法可获得氧化石墨烯制备的较优条件。机理分析结果表明:氧化石墨烯的不连续的π-π*共轭体系为主的结构特点是其紫外光谱在230 nm附近产生多个强度不同的吸收峰的原因。

Graphene oxide(GO) was prepared by chemical oxidation- sonicated crushing method with flake graphite, sulfuric acid and potassium permanganate as raw materials. The prepared GO was characterized by means of spectroscopy SEM, laser granulometer, FT-IR, UV-vis and AFM. The results show that the few-layered GO could be differentiated from the multi-layered graphite oxide in a solution of the mixture of the two by observing the variation of the intensity and the profile of absorption peaks around 230 nm in the UV- vis spectroscopy. Based on this phenomenon, the qualitative and quantitative analysis of graphene oxides in the solution can be realized. Thereby the optimal conditions for the preparation of graphene oxide can be obtained. It is proposed that the appearence of multi absorption peaks nearby 230 nm in the UV spectra of GO may be attributed to the existence of a peculiar structure of discontinues p-p* conjugated system in the graphene oxide.