不同形貌的金属和钨酸盐纳米粒子的制备

【作者】 周萍；

【导师】 包建春；

【作者基本信息】 南京师范大学 ， 物理化学， 2006， 硕士

【摘要】 本论文主要以聚乙二醇（PEG）为结构导向剂，进行了PdCo双金属纳米空心球和树枝状Pd纳米结构的制备及性质研究。此外，在十二胺、十一烯酸和正辛烷组成的反胶束乳状液体系中合成了不同形貌的BaWO₄纳米粒子及丝状CdWO₄纳米粒子。用透射电子显微镜（TEM）、高分辨透射电子显微镜（HRTEM）、扫描电子显微镜（SEM）、X-射线能量扩散光谱仪（EDS）、X-射线光电子能谱仪（XPS）、X-射线衍射仪（XRD）、紫外可见光谱仪（UV-vis）、富里叶变换红外光谱仪（FT-IR spectra）、激光拉曼散射光谱仪和荧光光谱仪对样品进行表征和结构分析。主要结果如下： 1．在聚乙二醇溶液体系中制得了PdCo双金属纳米空心球，直径主要分布在80nm左右，壁厚约为9nm。这是首次利用软模板合成含Pd的双金属纳米空心球的例子。成功地将PdCo双金属纳米空心球用于催化Sonogashira反应，该催化反应具有诸如环境友好（在水中进行反应）、催化剂重复回收使用、实验操作简单和反应产率高等优点。研究了PdCo纳米空心球的电化学储氢性质，测量结果表明其具有稳定的电化学循环性能以及很高的电化学容量，是一种潜在的储氢材料。研究了用PdCo纳米空心球修饰对LaNi₅合金电极电化学性质的影响，并与没有修饰的LaNi₅合金电极进行了比较。结果表明活化后，尤其是在高倍率放电时，用PdCo纳米空心球修饰的LaNi₅合金电极的放电平台电压和放电容量均有所升高。 2．在聚乙二醇溶液体系中制得了树枝状Pd纳米粒子，HRTEM测试表明，该树枝状Pd纳米粒子为单晶。初步讨论了树枝状Pd纳米粒子的生长机制，发现PEG对其晶体生长具有十分重要的作用。研究了树枝状Pd纳米粒子修饰玻碳电极（Pd／GCE）电催化还原H₂O₂的性能，结果表明该电极电化学响应快，具有明显的电催化还原H₂O₂活性，同时还原电流随着H₂O₂浓度的增加而增大，可以用于H₂O₂的定量检测。 3．在十一烯酸和十二胺为表面活性剂、正辛烷为油相形成的油包水（W／O）型反胶束体系中，通过调节体系的组成，制得了丝状、棒状和空心球状的BaWO₄纳米粒子，其中空心球状BaWO₄纳米粒子的制备为首次报道。对所制得不同形更多还原

【Abstract】 In this dissertation, polyethylene glycol （PEG） was used as a structure-directing agent to prepare PdCo bimetallic hollow nanospheres and dendritic Pd nanostructure. Also, CdWO₄ nanowires and BaWO₄ nanoparticles with different shapes, such as wire-like, rod-like, and hollow spherical, were prepared in different microemulsion systems using octane as oil, undecylenic acid and/or dodecylamine as surfactants. These nanostructures were characterized by transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, X-ray energy dispersive spectroscopy （EDS）, X-ray Photoelectron Spectrometer（XPS）, X-ray diffraction（XRD）, UV-vis spectroscopy, Fourier transform infrared（FT-IR） spectrometer, fluorescence spectrophotometer. The main results were as follows:1. Using PEG as a structure-directing agent, PdCo bimetallic hollow nanospheres with a diameter of about 80 nm a thickness of about 9 nm were for the first time synthesized. This new Pd-containing bimetallic hollow nanostructure was successfully applied to catalyze Sonogashira reaction, which reveals obvious advantages such as environmentally friendly reaction conditions （proceeded in water）, the recyclability of the catalyst, simple experimental operation and high yields. The measurements on the electrochemical hydrogen-storage of the PdCo bimetallic hollow nanosphere electrode revealed high electrochemical cyclic stability and larger electrochemical capacities, implying that it might be a premium material for hydrogen storage. The effect of such modification with the Pd-Co nanospheres on the electrochemical properties of the LaNi₅ alloy electrode was examined and compared with the pure LaNi₅ alloy electrode. It is shown that both the discharge potential plateau and the discharge capacity of the LaNi₅ alloy electrode increase with the modification of the Pd-Co nanospheres after activation, especially at high discharge rate.2. Dendritic Pd nanostructures were obtained by the reaction of diamide hydrate with [PdCl₄]^2- in PEG aqueous solution. The mechanism of the growth of the dendritic更多还原