电化学合成铂基纳米催化剂及其催化性能研究

Proton exchange membrane fuel cells (PEMFCs) have drawn a lot of attention due to their high efficiency and friendliness to environment. However, the commercialization of PEMFCs at large scale has been restricted by their high cost since the noble platinum is employed as catalyst in this type of devices. Shape-controlled synthesis of Pt-based nanoparticles can significantly increase the utilization rate of platinum, and enhance the catalytic performance, therefore decrease the demand of Pt in the devices and pave the way for the commercialization of PEMFCs at large scale. Wet-chemical method and electrochemical method are two popularly used methods during the shape-controlled synthesis of Pt nanoparticles. Compared with wet-chemical method, electrochemical method can produce surface-free nanoparticles since no surfactant is used during the process of synthesis. Without the surfactant adsorbed on the surface, it is more reliable to build relationship between the catalytic performance and structure. In this project, electrochemical method will be employed to shape-controlled synthesize Pt-based nanoparticles and the rules and mechanism for shape-controlled synthesis will be explored. The relationship between the catalytic performance at steady state and the shape, surface structure, size, composition etc. will be investigated systematically. In addition, identical location TEM (IL-TEM) is used to explore the mechanism of degradation of Pt nanocatalysts at single nanoparticle level. All of the research can make a direction for synthesis of high efficient Pt-based nanoparticles.

质子交换膜燃料电池以其高效率，清洁等特点受到人们的广泛关注与研究，但是昂贵的铂基催化剂严重制约了其大规模商业化。形状控制合成铂基纳米催化剂，能够极大地提高铂的利用率，同时大幅提高铂的催化活性，为降低铂的用量，促进质子交换膜燃料电池的大规模商业化起到重要作用。湿化学法和电化学法是形状控制合成铂基纳米催化剂比较常用的两种方法。相比较湿化学法，电化学法制备铂基纳米粒子的过程中无需添加任何表面活性剂，使得其表面清洁，能够真实地反映出其构效关系。本项目将采用电化学法形状控制合成铂基纳米催化剂，探索出形状控制合成铂基纳米催化剂的规律。研究所制备的铂基纳米催化剂在稳态测试条件下的催化活性与催化剂形状、晶面结构、粒径大小、组成等因素之间的联系。结合原位TEM的方法，从单个纳米粒子水平研究铂基纳米催化剂性能衰减的机理。这些研究为进一步制备出优异铂基纳米催化剂指明方向。

形状控制合成铂族金属纳米催化剂，能够极大提高贵金属的利用率，大幅提升其催化活性，是降低贵金属的用量，促进其大规模商业化的重要策略。化学法和电化学法是形状控制合成铂族金属纳米催化剂比较常用的两种方法。本项目主要采用电化学法形状控制合成表面清洁的铂族金属纳米催化剂，探索出了形状控制合成铂族纳米催化剂的规律，制备出系列具有完美晶面结构的纳米催化剂，并系统研究其构效关系；在电化学法制备表面清洁的铂族金属纳米催化剂的基础上，探索了化学法制备表面清洁的铂族贵金属纳米催化剂，并系统研究了其构效关系；在制备纯铂族贵金属纳米催化剂的基础上，运用电化学法及化学法成功制备了系列铂族金属合金纳米催化剂，并系统研究了其构效关系；在铂族金属纳米催化剂研究的基础上，探索了其它贵金属，例如金、银纳米材料的制备及性能研究。本项目面向国家需求，兼顾基础理论研究和应用研究，研究成果对于燃料电池及纳米电催化等领域具有重要的指导意义和应用价值。