促进型PtMoSi/C催化剂的制备、表征及电催化活性  

Preparation,Characterization and Electrocatalytic Properties of Promoted PtMoSi/C Catalysts

作　　者：蔡育芬[1] 刘军民[1] 廖世军[1] 

机构地区：[1]华南理工大学化学科学学院,广州510641

出　　处：《物理化学学报》2007年第1期92-97,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20476034)资助项目

摘　　要：采用甲醛还原、H2还原、肼还原三种方法制备了添加硅钼酸的PtMoSi/C阳极催化剂,并用XRD、XPS和TEM技术对催化剂进行了表征.XRD表明Pt粒子呈立方面心晶态结构,TEM显示PtMoSi/C催化剂粒径小(3-4nm),分布窄,分散性好.XPS分析可知Pt主要以0价,Mo主要以6价,Si主要以4价形态存在于催化剂中.同时通过循环伏安法和线性扫描法考察了制备方法和添加硅钼酸对催化剂电化学活性的影响.结果表明,甲醛还原法制备的PtMoSi/C催化剂(Pt、Mo的原子比为3∶1)对甲醇氧化的电化学性能和抗中毒性能优于自制的PtRu/C和E-TEKPtRu/C催化剂,可能是因为添加硅钼酸可以使活性组分的分散度提高,从而提高了催化剂的活性和抗毒性能.PtMoSi/C nanocatalysts were prepared by chemical reduction using formaldehyde, H2, and hydrazine as reducing agents, respectively. The nanocompositions were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, and transmission electron microscopy （TEM）. XRD patterns showed a face,centered cubic crystal structure, and TEM images indicated that the naaoparticles that were uniformly dispersed on carbon were 3-4 nm in diameter. XPS analysis revealed that the catalysts contained mostly Pt（0）, Mo（VI）, and Si（IV）. The effects of preparation methods and additives on the catalytic activity were then studied by linear sweep voltammetry （LSV） and cyclic voltammetry （CV）. It was found that the PtMoSi/C nanocatalysts （npt：nMo=3：1 was the optimal ratio of Pt to Mo） prepared using formaldehyde as reducing agent showed higher electrocatalyfic activity and better tolerance to poisoning species in methanol oxidation compared with the homemade PtRu/C and the commercial E-TEK PtRu/C catalysts, and this could be ascribed to the high dispersion of Pt nanoparticles on the carbon by the addition of silicomolybdic acid.

关 键 词：硅钼酸 直接醇类燃料电池 催化剂 

分 类 号：O643.36[理学—物理化学]