【作者】 莫笑萍；

【导师】 王世昌；

【作者基本信息】 天津大学 ， 化学工程， 2003， 博士

【摘要】 纳米材料具有一系列新异的物理、化学特性，有广阔的应用前景。获得大量的、尺寸可控的、成本较低的纳米材料仍然是一个极具挑战性的课题，也是纳米材料得到广泛应用的前提。所以，纳米材料的制备研究具有十分重要的意义。聚吡咯具有稳定性好，电导率高，容易合成等优点，在应用方面有着广阔的前景。聚吡咯易形成不溶不熔的颗粒状，难以加工成型，限制了它的应用。定向生长的聚吡咯纳米线具有更高导电性和机械强度，在分子导线、材料增强和修饰电极等方面具有更加诱人的前景。使得聚吡咯纳米线的制备成为研究热点。研制成功定向生长法制备聚吡咯纳米线。不使用任何模板，在水溶液体系中，采用电化学方法，在石墨电极表面快速、低成本合成了聚吡咯纳米线。研究表明，聚吡咯纳米线的形成经历二维瞬时成核和一维生长过程。聚吡咯纳米线的形貌受聚合电位、电化学方法、单体浓度、支持电解质浓度及聚合时间等合成条件的影响。形成聚吡咯纳米线的聚合电位范围为0.75～0.95 V。通过对合成条件的控制，合成了直径分布由40 nm到150 nm不等的聚吡咯纳米线。利用红外光谱测量分析了聚吡咯纳米线的电导率，最高为186 S/cm。使用自行设计的聚吡咯膜表观电导率装置测量了聚吡咯纳米线结构膜的表观电导率，与红外光谱法得到的电导率相比，聚吡咯纳米线结构膜的表观电导率小一个数量级。首次研究了聚吡咯纳米线修饰电极在pH传感器方面的应用。结果表明，聚吡咯纳米线修饰电极对pH的具有良好的响应，且不受膜厚影响，容易制得具有稳定响应的pH传感器。对聚吡咯纳米线用作pH传感器的制备条件的优化进行了探索，提出聚吡咯对pH的响应机理，并建立数学关系式。研究了聚吡咯纳米线及分散有普通金属Fe、Ni、Cu的金属/聚吡咯纳米线复合电极对电解析氢反应的催化性能，同时用不同的方法制备了金属/聚吡咯复合电极。研究表明，与石墨电极相比，金属（Fe、Ni、Cu）/聚吡咯电极对电解析氢反应有较好的催化性能。研究了半导体CdS纳米粒子的制备及表征。半导体CdS纳米粒子具有优异的发光、光电转化等性能，近年来倍受关注。本文以巯基乙酸为稳定剂，在水溶液中制备了CdS纳米粒子，用UV-Vis吸收峰的蓝移和透射电镜对CdS纳米粒子的尺寸进行了评估。研究表明，CdS纳米粒子粒径及稳定性受诸如溶液温度、pH、稳定剂与S2-之间的比值等反应条件的影响；在常温下，HSCH2COOH与S2-的摩尔比为3.5，pH＝9.0，得到了长期稳定、直径约为2.4 nm，粒度分布可达±5%的CdS纳米粒子。用电子衍射测得CdS纳米粒子为立方晶型。更多还原

【Abstract】 Having a serial of unique physical and chemical properties, nanomaterials are prospecting to be applied in many fields. However, it is still a challenge to get a large amount of nanomaterials with controlled size cheaply. Therefore, study on the preparation of nanomaterials is one of the most pressing tasks at present.Polypyrrole is especially promising for commercial applications because of its good stability, facile synthesis and higher conductivity than many other conducting polymers. However, under usual conditions polypyrrole is insoluble and infusible, which restrict its processing and applications. The emergence of molecular conductive wire also makes it important to synthesize polypyrrole nanowires. Polyporrole nanowires were synthesized electrochemically on the graphite electrodes in aqueous solution within a few minutes even decades of seconds. The experimental results demonstrated that polypyrrole nanowires grow with two-dimensional instantaneous nucleation process and one-dimensional growth pattern. The appearance of the polypyrrole nanowires is affected by polymerization potential, electrochemical method, pyrrole and electrolyte concentration and polymerization time. Polypyrrole nanowires could be synthesized only when the polymerization potential is between 0.75 V and 0.95 V. Polypyrrole nanowires with diameters 40 nm～150 nm were synthesized by controlling the synthetic conditions. FTIR spectra of the polypyrrole nanowires shows that the intrinsic conductivity decreases with the increase of the polymerization potential and the highest intrinsic conductivity is 186 S/cm. The conductivity of the polypyrrole film with nanowire morphology was measured using the device designed by ourselves. This conductivity is three orders lower than polyporrole intrinsic conductivity.The application of the polypyrrole nanowire modified electrode in the pH sensor was studied. The results showed that the film thickness has no affect on the pH potentiolmetric response of the film, so it is easy to make pH sensors with the same response. The effect of synthetic conditions on the pH response was studied. In order to further understand the process and phenomena that determine the performance of the polypyrrole nanowire film as a pH sensor, the pH potentiolmetric response mechanism of the polypyrrole nanowire film was studied and a formulation that fits this mechanism has been established. The catalytic performances of polypyrrole nanowires during hygrogen evolution <WP=4>reaction were also studied, so as the metal (respective Fe, Ni, Cu) /polypyrrole nanowires composite electrodes. It was revealed that they all had better electrocatalysis than graphite electrode.Here, the preparation of CdS semicondutor nanoparticles was studied too. CdS semicondutor nanoparticles have been attracting much attention in the recent years for its outstanding luminescence and photoelectricity translating properties. In this work, CdS nanoparticles were prepared by using SHCH2COOH as the stabilizer. UV-Vis absorbance spectrum and transmission electron microscopy (TEM) were successfully employed to evaluate the size of the CdS nanoparticles. The size and stability of the particles are affected by the preparation conditions such as reaction temperature, concentration of SHCH2COOH and pH of the solution. CdS nanoparicles with diameter 2.4 nm were prepared at room temperature in a solution with pH=9.0 and the value HSCH2COOH/S2-=3.5. The size distribution of the CdS nanoparticles is ±5% with a long-time stability.更多还原