通过低温氧化法在活性碳表面修饰聚吡咯（PPy-C）,并以PPy-C为载体制备了纳米Pd催化剂（Pd/PPy-C）.采用X射线衍射、扫描电镜、透射电镜等手段对载体PPy-C及催化剂Pd/PPy-C进行了表征,电化学测试结果表明,Pd/PPy-C催化剂电极不但能够增强催化剂对甲酸催化氧化的活性,而且还能够大幅度提高催化剂的稳定性,因此以PPy-C为载体的Pd/PPy-C催化剂是一类具有潜在应用前景的直接甲酸燃料电池阳极催化剂.通过分析电化学比表面随循环伏安次数的变化及多电势阶跃实验结果表明,催化剂电极活性衰减的主要原因是载体被氧化及电极表面积累强吸附物种的结果.%Direct formic acid fuel cells are environmentally friendly technologies and have attracted more and more attention as a new generation of power source.Pd is an important noble metal that is widely used in heterogeneous catalysis.In order to disperse Pd nanoparticles and to improve their catalytic efficiency and stability,polypyrrole are generally used as supporting materials due to their structures and electrical properties.In this work,polypyrrole composite（PPy-C） encompassed of carbon black are synthesized by low temperature oxidation of pyrrole on carbon black and the nanosized Pd catalyst supported by PPy-C is prepared.The support PPy-C and the catalyst Pd/PPy-C are characterized by X-ray diffraction,scanning electron microscopy and transmission electron microscopy.The TEM results show that the morphology of Pd/PPy-C and Pd/PPy-C is not the same.Pd deposited on PPy-C are nanoparticle clusters.The average particle size of metal Pd in Pd/C and Pd/PPy-C catalysts are 4.2 and 3.8 nm obtained from XRD diffraction peak.The results from formic acid oxidation show that the Pd/PPy-C catalyst exhibits better activity and stability in contrary to Pd/C.After 160 potential cycles,the formic acid oxidation current reduced to 8% of the first lap on Pd/C,but 50% on Pd/PPy-C.Therefore,the Pd/PPy-C catalyst is a promising anode catalyst in direct formic acid fuel cells.By analyzing formic acid oxidation current in the experiment of multi-step potential,it shows that the main reasons of the decrease of the oxidation current are the unstabitily of the support and the strong adsorption species on the electrode surface.
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