石墨烯和二硫化钼修饰电极的电化学检测及析氢效应研究

发布时间：2018-04-22 06:38

本文选题：石墨烯 + 二硫化钼　；参考：《西北大学》2017年硕士论文

【摘要】：石墨烯和二硫化钼的结构类似,均为层状结构且具有众多优异性能,本硕士论文通过将石墨烯的高导电性与二硫化钼的优异性能相结合,分别探究了其合成制备机理、形貌结构、化学组成等,进而研究了二者相互结合后在电化学传感器和电催化析氢方面的应用。主要包括以下内容:(1)使用氧化还原法制备石墨烯,以钼酸钠和L-半胱氨酸分别为钼和硫的前驱体,水热法合成二硫化钼,并对石墨烯和二硫化钼的制备机理进行分析。通过XRD、XPS、SEM、EDX等方法对产物晶体结构、化学组成以及形貌特征进行测试表征。研究结果表明:①通过控制pH,可以更好的促进氧化石墨烯还原过程的进行,得到水分散性良好的石墨烯。XRD表征结果表明该实验制备的石墨烯为多层石墨烯,.XPS结果表明石墨烯的还原较为完全,TEM影像则揭示了石墨烯的褶皱结构,表明其具有较大的比表面积。②制备出具有3D花状结构的二硫化钼。通过XRD表征了二硫化钼的晶体结构,XPS和EDS分析得出元素价态以及原子比充分证明了产物就是二硫化钼,而SEM以及TEM则清楚的揭示了合成的二硫化钼为直径200nm左右花状结构。TEM显示二硫化钼晶面间距为0.62nm。(2)通过逐步修饰法得到石墨烯-二硫化钼修饰电极,并作为电化学传感器应用检测多巴胺,采用CV和DPV法对实验条件和电化学反应行为进行研究,结果表明:PH=7.5,修饰量为10μL,富集时间为3 min为检测的最佳实验条件,扫速与峰电流的关系表明多巴胺在修饰电极上的反应受吸附控制,最终得到该传感器对多巴胺的检测浓度范围为5.0×10-8-1.0×10-5mo1/L,浓度与峰电流之间表现出很好的线性关系,其回归方程为Ipa =12.63c + 0.4950(R=0.999),信噪比S/N=3时计算得到该方法的检出限为7.13×10-9 mol/L。结果表明该方法具有较好的重复性稳定性以及抗干.扰能力,血清样品的加标检测结果显示回收率良好(96.0-101.4%),可以成功应用于实际样品中的多巴胺评估。(3)制备石墨烯与二硫化钼的复合物,研究了不同的二硫化钼以及复合物的电催化析氢效果。SEM测试结果显示水热合成的复合材料保留了二硫化钼的立体花状结构,同时石墨烯的加入减小了二硫化钼花状结构的尺寸,EIS阻抗谱表明材料具有极佳的导电性。LSV等一系列测试和数据处理结果表明石墨烯/二硫化钼复合材料的电催化析氢效果最佳,其析氢起始电位为125mV,塔菲尔斜率为54mV/dec,并且具有较好的稳定性。
[Abstract]:The structures of graphene and molybdenum disulfide are similar, both of them are layered and have many excellent properties. In this thesis, the synthesis mechanism of graphene and molybdenum disulfide was studied by combining the high conductivity of graphene with the excellent properties of molybdenum disulfide. The application of the two in electrochemical sensor and electrocatalytic hydrogen evolution was studied. The main contents are as follows: (1) graphene was prepared by redox method. Molybdenum disulfide was synthesized by hydrothermal method using sodium molybdate and L-cysteine as precursors, respectively. The preparation mechanism of graphene and molybdenum disulfide was analyzed. The crystal structure, chemical composition and morphology of the product were characterized by means of XRDX and XRDX. The results show that the reduction process of graphene oxide can be better promoted by controlling the pH value of 1: 1. The results of XRD characterization of graphene with good water dispersibility indicate that the graphene prepared in this experiment is multilayer graphene. XPS results show that the reduction of graphene is relatively complete and TEM images reveal the fold structure of graphene. The results showed that molybdenum disulfide with 3D flower-like structure was prepared with large specific surface area of .2. The crystal structure of molybdenum disulfide was characterized by XRD and EDS. The valence state and atomic ratio of molybdenum disulfide were fully proved that the product was molybdenum disulfide. SEM and TEM clearly revealed that the synthesized molybdenum disulfide was a flower-like structure with diameter of 200nm. Tem showed that the crystal plane spacing of molybdenum disulfide was 0.62nm.m-2) the graphene molybdenum disulfide modified electrode was obtained by stepwise modification. As an electrochemical sensor, dopamine was detected by CV and DPV. The experimental conditions and electrochemical reaction behavior were studied. The results showed that the optimal experimental conditions were as follows: (1) PH7. 5 渭 L, 10 渭 L, and 3 min, respectively. The relationship between sweep speed and peak current indicates that the dopamine reaction at the modified electrode is controlled by adsorption. Finally, the detection concentration of dopamine by the sensor is 5.0 脳 10-8-1.0 脳 10-5mo-1 / L, and the linear relationship between the concentration and the peak current is very good. The regression equation is Ipa 12.63c 0.4950mol / L, and the detection limit is 7.13 脳 10 ~ (-9) mol / L calculated by S / N = 3. The results show that the method has good repeatability stability and dry resistance. The results of standard detection of serum samples show that the recovery rate is good, 96.0-101.4%, which can be successfully used to prepare the complex of graphene and molybdenum disulfide. The results of electrocatalytic hydrogen evolution of different molybdenum disulfide (MoS) and its complexes. SEM results showed that the composites prepared by hydrothermal method retained the solid flower-like structure of molybdenum disulfide. At the same time, the addition of graphene reduced the size of molybdenum disulfide flower structure and EIS impedance spectroscopy showed that the materials had excellent conductivity. LSV and data processing results showed that the graphene / molybdenum disulfide composite had the best effect of electrocatalytic hydrogen evolution. The initial hydrogen evolution potential is 125 MV, the Taffel slope is 54 MV / r, and it has good stability.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O646.54;TP212.2

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