【作者】 刘洋；

【导师】 冶保献；

【作者基本信息】 郑州大学 ， 环境科学， 2013， 硕士

【摘要】 碳材料由于其较高的导电性、对许多氧还原反应体现出了很高电催化活性,使之成为电化学分析领域应用最为广泛的材料。鉴于石墨烯具有极为特殊的物理及化学属性,大比表面积性质、锯齿型边缘、室温下较高的电子迁移速率,科学界越来越多的科研工作者加入到了石墨烯性能研究和合成的行列当中。氧化石墨烯(GO)是石墨烯的氧化产物,同时也是化学还原法制备石墨烯的中间产物。氧化石墨烯与石墨烯的最大不同之处在于其分子片层表面含有较多活性含氧基团,这些含氧基团赋予了氧化石墨烯更多的性质,如可以在水中良好的分散,电子传导速率的提高等等。目前科学界对于石墨烯和氧化石墨烯的研究较多,但是还未有人对于石墨烯和氧化石墨烯进行比对研究。本文正基于此现状准备对石墨烯、氧化石墨烯的电化学性质进行比对研究。(一)利用改良的后的Hummer法,同时借助于超声辅助作用制备氧化石墨烯,然后利用水合肼还原合成石墨烯。并通过红外、XRD、透射电镜、原子力显微镜进行形态表征。结果令人满意,在表征过程中发现氧化石墨烯的片层表面比石墨烯片层表面还有更为丰富且活跃的含氧基团,氧化石墨烯的平面结构较平整,而石墨烯的平面呈现出了褶皱。(二)利用石墨烯、氧化石墨烯与Nafion结合制备出两种的电化学传感器Nafion/graphene/GC和Nafion/GO/GC,通过其对水中的金属离子Pb2+进行电化学检测,结果显示在,Nafion/GO/GC测定的氧化峰电流ip与Pb2+的浓度的线性范围比Nafion/graphene/GC宽,检出限分别为1.0×10-7mol L-1、2×10-8mol L-1。我们借此判断出氧化石墨烯对金属比石墨烯修饰电极有更好的吸附作用。(三)我们借助于Nafion/graphene/GC和Nafion/GO/GC对对氨基酚进行电化学检测,并简单研究其电极反应机理。发现两电极的电极反应机理几乎一致,但是氧化石墨烯修饰电极的检测限比石墨烯修饰电极要低半个数量级。我们推断是氧化石墨烯由于其表面的较多丰富而活跃的含氧基团的存在提高了电极表面的电子转移速率。更多还原

【Abstract】 Carbon materials, due to the high electrical conductivity and the excellent electrocatalysis, have become the most widely used electrode materials in the field of electrochemical analysis. In view of the fact that graphene has very special physical and chemical properties such as:the large specific surface area, a zigzag edge, the high electron mobility rate at room temperature, more and more researchers in scientific community are joining in the research and synthesis of the graphene. Graphene Oxide (GO), as well as the oxidation product grapheme, is an intermediate of the Graphene preparation by chemical reduction. And it is an important member of the graphene derivatives family. The biggest difference between GO and graphene is that there are abundant active oxygen-containing groups on the surface of GO molecular slice. These oxygen-containing groups bring some properties such as: evenly dispersed in the water and the higher electron mobility rate. There are so many scientists in scientific community joining in the research of the graphene and GO in recent years. However, the report about the comparison research between GO and graphene has not emerged yet. In this paper, the electrochemical properties of the graphene with the GO were compared based on the status quo.1. The GO was prepared by graphite oxide reduction method (improved Hummers method) with the aid of ultrasonic. Then the oxygen-containing groups were removed by chemical reduction-the hydrazine hydrate reduction method. The morphological characterizations and physical properties of graphene and GO were confirmed by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscope (AFM). Results showed that there are more abundant active oxygen-containing groups on the slice layer surface of GO than that of the graphene. Meanwhile, the molecular slice of the graphene exhibited drape, while the plane structure of the GO was flat and level. These all proved that graphene and GO were successfully composed.2.In this paper, the graphene and GO, accompanied with nafion, were used to construct electrochemical sensor, and the modified electrodes (Nafion/graphene/GCE and Nafion/GO/GCE) were applied for the determination of metal ions Pb2+in water. Differential pulse anodic stripping voltammetry (DPASV) was adopted to investigate the analytical performance of Nafion/graphene/GCE and Nafion/GO/GCE to lead (Pb2+). It turned out that the Nafion/GO/GCE showed a better performance for the determination of Pb2+than Nafion/graphene/GCE. the detection limit of Nafion/graphene/GCE and Nafion/GO/GCE is1.0×10-7and2×10-8mol L-1. These all proved that the GO modified electrode had better adsorption effect to the metals contrasting with the graphene. In addition, the stability of Nafion/GR/GCE was better than that of Nafion/GO/GCE.3. The electrochemical detection and possible mechanism of aminophenol was studied on Nafion/graphene/GCE and Nafion/GO/GCE using square wave voltammetry (SWV). Results showed that the redox reaction mechanism of aminophenol was consistent on the two sensors, while the detection limit of aminophenol on Nafion/graphene/GCE was half an order of magnitude larger than that of Nafion/GO/GCE. This possible reason might that the oxygen-containing groups on the surface molecular slice of GO improved the electron transfer rate the electrode surface.更多还原