【作者】 周振华；

【导师】 辛勤； 孙公权；

【作者基本信息】 中国科学院研究生院（大连化学物理研究所） ， 物理化学， 2003， 博士

【摘要】 担载型高载量的铂基催化剂被广泛用作直接甲醇燃料电池的阴阳极电催化材料。本论文以探索该类催化剂的制备新方法为主，考察了各种不同制备参数对催化剂金属分散度及形貌的影响，并通过原位及非原位的手段表征了催化剂制备过程中反应体系的变化，从而理解制备过程的反应机理及金属粒子形成、长大及与载体的相互作用机理。在此基础上，比较性的研究了新方法制备的铂基催化剂与同型的商品催化剂的金属粒径、形貌、电化学活性及稳定性。最后还初步探索了Pt-MO₂C／C、Pt-MoP／C及PtRu-MoP／C催化剂作为新型阳极电催化材料的可能性。 制备参数的考察结果表明，反应体系的pH值、还原温度、加水量及其顺序、浸渍时间及其光照对多元醇还原法所制催化剂的金属粒径及形貌有较大影响。采用该方法，通过调变制备条件，可将所制催化剂的金属粒径有效控制在各种不同的纳米尺寸。对制备过程的表征结果表明，绝大多数金属粒子首先在溶液相中形成，通过加入沉降剂后，因静电作用而沉降于炭载体的表面。 通过XRD、TEM及化学吸附表征，结果表明，采用多元醇还原法制备的铂基催化剂比同型的商品催化剂金属粒径更小，且分布更均匀。其单池性能测试结果表明，采用该方法制备的催化剂比同型的商品催化剂活性更高，稳定性更好。 初步探索了Pt-MO₂C／C、Pt-MoP／C及PtRu-MoP／C催化剂的制备条件及作为新型阳极电催化材料的活性与稳定性。结果表明，贵金属载量为3wt％的Pt-Mo₂C／C在放电条件下即能稳定存在，但低贵金属载量的催化剂活性均比较差。即使是同样贵金属载量的Pt-M02C／C、Pt-MoP／C及PtRu-MoP／C催化剂的活性也都比PtRu／C催化剂低。更多还原

【Abstract】 Highly dispersed carbon supported Pt based metal catalysts with high metal loading (40~60wt.%) are known to be efficient electrocatalytic material in direct methanol fuel cells (DMFCs). hi this dissertation, a novel synthesis of this kind of electrocatalysts was explored and the effects of several preparation variables on the particle size and morphology of electrocatalysts were studied. Some in-situ and ex-situ techniques were employed to provide clues for fundamental understanding of preparation process. The particle size, morphology, electrocatalytic activity and stability of in-house electrocatalysts were measured and compared to the same type of commercial electrocatalysts. hi addition, some preliminary exploration on Pt-MoiC/C, Pt-MoP/C and PtRu-MoP/C as new anode electrocatalysts were carried out.Optimizing experiments of preparation variables show that pH value, reduction temperature, addition sequence and volume, impregnation duration and lighting all have significant influence on the particle size and morphology of as-synthesized electrocatalysts during polyol process. The particle size of the electrocatalysts can be finely tuned to favorable nanometer size by changing some preparation variables by this method. Characterization of preparation process inferred that most of the metal particles formed in solution firstly and then deposited to carbon support after addition of sedimentation agent.The results of XRD, TEM and chemisorption consistently demonstrate that nanopaticles in in-house electrocatalyts are smaller and much uniform than that of the same type of commercial electrocatalysts. The single DMFC employing in-houseelectrocatalysts exhibit higher performance and better stability compared to the commercial electrocatalysts.Some preliminary exploration on Pt-MoiC/C, Pt-MoP/C and PtRu-MoP/C as new anode electrocatalysts were carried out to study their preparation, activities and stabilities in DMFC. The results display that the Pt-Mo2C/C with 3wt.% Pt loading has good stability during the cyclic voltammetry. However, the performance of single DMFC employing these electrocatalysts is lower than that of PtRu/C electrocatalyst.更多还原