【作者】 赵晓娟；

【导师】 王春明；

【作者基本信息】 兰州大学 ， 分析化学， 2015， 博士

【摘要】 本博士学位论文以石墨烯(Graphene, GN)、类石墨烯二维层状材料为功能化修饰剂,通过掺杂、自组装等手段,制备了相应的修饰玻碳电极。对所制备的修饰电极分别采用X-射线衍射(XRD)、透射电镜(TEM)、X射线光电子能谱(XPS)等多种分析手段进行了系统的表征,并研究了所制备修饰电极在电化学分析及电催化析氢方面的应用。主要研究内容包括：1.采用乙二醇还原法制备了CuS纳米粒子(NPs)修饰的石墨烯纳米复合材料(CuS/GN),成功构建了基于CuS/GN的电化学传感器,并将其用于七叶亭的电化学分析研究。CuS/GN复合材料分别用XRD及TEM表征。采用循环伏安法(CV)和差示脉冲伏安法(DPV)研究了七叶亭在修饰电极上的电化学行为。结果表明,CuS纳米颗粒和石墨烯之间的相互协同作用加强了七叶亭在电极上的电化学响应。在最优化条件下,得到了七叶亭的标准曲线,其线性范围为1.O×10-7～1.0×10-4mol L-1,检测限为5.8×10-8 mol L-1。该电化学传感器表现出了较好的重现性和稳定性,具有良好的选择性和灵敏度,能用于实际样品中七叶亭的检测。2.采用简单、环境友好的水热法一步制备了CeO2/GN复合材料,成功构建了基于CeO2/GN的电化学传感器,并将其用于麝香草酚的灵敏检测。采用XRD、TEM和XPS对CeO2/GN复合材料进行了表征。与裸玻碳电极(GCE)相比,该电极具有良好的催化氧化麝香草酚的性能。在最优化条件下,得到了麝香草酚的标准曲线,线性范围为1.0×10-7～1.8×10-5mol L-1,检测限为5.0×10-8 mol L-1。该修饰电极用于实际样品中麝香草酚的检测,具有较高的灵敏度和选择性。3.通过水热反应一步合成了MoS2/GN纳米复合材料,成功构建了基于MoS2/GN的电化学传感器,并将其用于和厚朴酚的灵敏检测。采用XRD、TEM和XPS对其进行了表征,用CV和DPV研究了和厚朴酚在修饰电极上的电化学行为。实验结果表明,MoS2和Graphene的结合,提高了和厚朴酚的电化学响应。在最优化条件下,得到了和厚朴酚的标准曲线,线性范围为1.0×10～9-2.5×10-6 molL-,检测限为6.2×10-10 mol L-1。将该修饰电极用于实际样品中和厚朴酚的检测,得到了满意的结果。4.通过溶剂热法制备得到了MoS2/MoSe2纳米复合材料,将其用作析氢反应(HER)催化剂。采用TEM和XPS对复合材料进行了表征,结果表明,复合材料由褶皱的MoS2/MoSe2纳米薄片组成。用线性伏安(LSV)、恒电位长时间电解等电化学技术评价了该电极的析氢电催化性能和稳定性,由实验结果可知,由于薄层结构中存在丰富暴露的S和Se的边缘,加之MoS2与MoSe2之间有效的相互协同作用,加强了MoS2/MoSe2催化剂对HER的催化性能,使其具有较低的起始电位0.40 V (vs. SCE),并且在过电位为0.45 V(vs. SCE)时,就具备较大的阴极电流密度(4.84 mA/cm2)。因此,MoS2/MoSe2纳米复合材料可以用作替代贵金属材料的高效电解水催化剂,有望被广泛应用于低成本的电化学制氢过程中。更多还原

【Abstract】 In this paper, graphene(GN) and MoS2 were used as original material to prepare several nanocomposites. The X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and a variety of analytical methods were used to characterize these nanocomposites. Then we studied the nanocomposites in electrochemical analysis and catalysis application. The contents of this thesis were described as follows:1. CuS/GN nanocomposites were synthesized via reduction of ethylene glycol. An electrochemical sensor based on CuS/GN nanocomposites was fabricated for sensitive detection of esculetin. The nanocomposite was characterized by XRD and TEM. The electrochemical behavior of esculetin was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results indicated that the synergistic effect between CuS nanoparticles (NPs) and graphene enhanced the electrochemical response of esculetin. Under the optimal conditions, the DPV peak current increased linearly with the esculetin concentration in the range from 1.0×10-7 to 1.0×10-4 mol L-1, and the detection limit was 5.8×10-8 mol L-1. Furthermore, a good selectivity with high sensitivity was obtained for the determination of esculetin in real samples.2. A novel thymol electrochemical sensor based on CeO2 nanoparticles-decorated graphene hybrid was introduced. The hybrid was characterized by XRD, TEM and XPS. The electrochemical behavior of thymol on the CeO2/GN modified glassy carbon electrode was investigated by CV and DPV. Compared with bare glassy carbon electrode, the proposed electrode showed improved analytical performance characteristics in catalytic oxidation of thymol. Under the selective conditions, the modified electrode showed a linear voltammetric response for the thymol within a concentration range of 1.0×10-7 to 1.8×10-5 mol L-1, and a value of 5.0×10-8 mol L-1 was calculated for the detection limit. Furthermore, a good selectivity with high sensitivity was obtained for the determination of thymol in real samples.3. A novel honokiol electrochemical sensor based on MoS2/GN nanohybrid was introduced in this work. The hybrid was characterized by XRD, TEM, SEM and XPS. The electrochemical behavior of honokiol on the MoS2/GN modified glassy carbon electrode was investigated by CV and DPV. The proposed electrode showed improved analytical performance characteristics in catalytic redox of honokiol. Under the optimal conditions, the modified electrode showed a linear voltammetric response to the honokiol with a concentration range from1.0×10-9 to 2.5×10-6 mol L-1, and the detection limit was estimulated at 6.2×10-10 mol L-1. Moreover, the sensor also exhibited good reproducibility and stability, and could be used for the detection of honokiol in pharmaceutical samples.4. The MoS2/MoSe2 hybrid was synthesized by a solvothermal reaction. The hybrid was characterized by XRD, TEM and XPS. Due to highly exposed S and Se active edges and significant synergistic combination of MoS2 and MoSe2, the MoS2/MoSe2 catalyst exhibits superior hydrogen evolution reaction (HER) activity with a low overpotential of about 0.40 V (vs. SCE) and a large cathodic current density (4.84 mA/cm2 at an overpotential of 0.45 V). Therefore, the MoS2/MoSe2 hybrid could be expected to split water with high efficiency and ensure a renewable and economical production of hydrogen.更多还原