【作者】 赵静；

【导师】 李永军；

【作者基本信息】 湖南大学 ， 分析化学， 2010， 硕士

【摘要】 纳米材料具有不同于本体材料的物理和化学特性以及良好的生物兼容性等,已经广泛地应用于信息存储、医学诊疗、催化以及传感分析等领域。研究纳米材料自组装不仅可以从微观上解释纳米微粒之间的相互作用机理,实现纳米微粒组装的可控性,而且能够通过研究获得的纳米微粒的组装体发现某些新的性质,从而促进纳米材料的推广和应用。本文研究了金、铂纳米微粒的自组装行为及某些组装体的电催化性能,具体内容如下：1.金纳米粒子自组装。以2-巯基乙胺为偶联剂,通过控制偶联剂浓度、搅拌速率、反应时间、超声强度及盐浓度等因素,将3.5 nm的金纳米粒子组装成具有不同微观结构的组装体,如：球状、环状及两瓣状等,并初步分析了其组装机理,丰富了纳米微粒的组装结构。2.铂纳米粒子原位自组装。用乙二醇作为还原剂和溶剂,在溶液中将～3.5 nm的铂粒子原位组装成较大粒径的纳米粒子组装体。由于实验过程中没有加入保护剂,保持了粒子表面的活性,有效地提高了铂催化剂对甲醇氧化的催化效率和抗毒化能力3.金、铂纳米微粒二维复合薄膜组装。在金纳米粒子单层膜基底上,采用欠电位沉积与置换反应相结合的方法,制备了Pt／Au二维复合纳米结构,并通过层层组装的方法,制备了以Pt／Au为结构单元的(Pt／Au)n型多层复合组装体。其中,通过调节欠电位沉积的次数,控制铂纳米层的数目,进而得到Ptm／Au及(Ptm／Au)k纳米结构组装体。将以上所制备的复合薄膜应用于甲醇的电催化氧化发现,薄膜的催化性能及抗毒化能力主要受其结构影响。金与铂的接触面越多,其催化性能及抗毒化能力就越好。在制备的所有复合薄膜中,(Pt／Au)3结构的效果是最好的,且其抗毒化能力比商业催化剂Pt／C提高了69%。更多还原

【Abstract】 Nanometer materials have been widely used in various fields due to their unique physicochemical properties and good biocompatibility, such as information storage, medical diagnosis, catalysis and sensing. Researches on self-assembly of nanometer materials can not only reveal the interaction mechanisms between nanoparticles to further control the process of nanoparticle self-assembly, but also make for discovering new properties of nanoparticle assemblies. All these studies are necessary for the development and application of nanometer materials. This thesis involves self-assembly of gold, platinum nanoparticles and electro-catalytic properties of some assemblies. The main research contents are as follows:1. Self-assembly of gold nanoparticles.2-mercaptoethylamine serving as coupling agents was added into 3.5-nm Au colloidal solution to fabricate Au nanoparticle assemblies with different nanostructures, such as spherical, annular and valvular, expanding the structure patterns of Au nanoparticle assemblies. The formation of these nanostructures depended on coupling agents concentration, stirring speed, reaction time, ultrasonic intensity and salt concentration. Additionaly, the assembly mechanism was also simply discussed.2. In-situ self-assembly of platinum nanoparticles. Platinum nanoaprticle assemblies were assembled via the self-aggregation of～3.5 nm Pt nanoparticles directly prepared in the polyol process. The assembling process does not involve any linker reagent. Thus, the as-prepared Pt nanoparticle assemblies showed satisfactory electro-catalytic activity for methanol oxidation, which is reasonably attributed to the high activity of Pt nanoparticle surface.3. Assembly of gold and platinum nanoparticles into two-dimensional composite structures. Au nanoparticle monolayer prepared at n-butanol/water interface was used as a substrate, Pt nanoparticles was modified onto Au nanoparticle monolayer by combining under-potential deposition and redox replacement, forming two-dimensional Pt/Au composite film. What’s more, (Pt/Au)n multilayer composite structures were also prepared via layer-by-layer assembly of Pt/Au units. The thickness of platinum layers in Pt/Au composite film can be controlled by repeating under-potential deposition and redox replacement procedures. Thus, Ptm/Au and (Ptm/Au)k multilayer composite films were also fabricated. All as-prepared composite films were used as anode catalysts for methanol electro-oxidation. The results showed that the catalytic efficiency and stability are closely related to the structures of catalyst films. The more interface between Au and Pt nanoparticles in catalyst films are, the better their catalytic efficiency and stability are. The structure of (Pt/Au)3 exhibits the best catalytic efficiency among all films, and its poison-resistant capability is 169% of that of commercial Pt/C catalyst.更多还原