改进多元醇法制备Pt/C催化剂及其性能表征

采用多元醇法和一种新的改进多元醇法制备了用于质子交换膜燃料电池的Pt/C催化剂,并对2种方法制备的催化剂进行了比较。后者是将Pt前驱体先负载至碳黑上,再加入多元醇还原,制备出了粒度分布均匀,分散性好的Pt/C催化剂。利用透射电镜(TEM)、X射线衍射(XRD)以及动态伏安法(CV)表征催化剂的微观组织形貌、物相组成以及电化学性能。研究结果表明,先还原后负载方式的多元醇法制备的Pt/C催化剂容易团聚。而先负载后还原方式制备的Pt/C催化剂则粒度分布均匀,分散性好,粒径大小在1.2～3.2 nm,电化学测试也表明,该Pt/C催化剂的质量电流密度为23.42 A/g,具有更高的催化活性。

Preparation and Characterization of Pt/C Catalysts by Modified Polyol Method

Supported Pt/C catalysts used in proton exchange membrane fuel cells(PEMFC) were prepared by a traditional polyol process and a modified polyol method,and then compared.In the so-called modified polyol process,highly monodispersed nanoparticles and homogeneous distribution on the carbon support can be obtained by reduction of Pt metallic precursors previously supported on carbon powders.TEM,XRD and CV were carried out to characterize the morphology,composition and the electrochemical properties of the Pt/C catalysts.It was found that the Pt/C catalysts prepared using the traditional polyol process as the reduction before support(RS) were liable to agglomeration.But Pt/C catalysts prepared by the modified polyol method with support before reduction(SR) had a better distribution and uniform particle dispersity with the average diameter in the range of 1.2~3.2nm.Cyclic voltammograms show that the as-prepared catalyst latter exhibited better electrochemical performance with the mass activity(MA) of 23.42 A/g.