银修饰对钯/石墨烯电催化活性的促进效果

摘要

采用电化学法,对石墨烯负载的Pd纳米粒子表面进行少量的Ag沉淀修饰,用于碱性介质下的1,2-丙二醇电催化氧化反应,检验 Ag修饰对Pd/石墨烯电催化活性的影响。仪器和电化学分析和表征结果表明有小部分的 Pd纳米粒子表面被 Ag所覆盖。虽然 Ag的沉积降低了Pd的表面积,而且 Ag 对1,2-丙二醇氧化反应没有电催化活性,但 Ag修饰的Pd/石墨烯与Pd/石墨烯相比具有更高的电催化活性。如 Ag与Pd原子比为1∶38的 Ag 修饰的Pd/石墨烯上1,2-丙二醇氧化反应的峰电流密度为 Pd/石墨烯上的1.9倍。这表明 Ag 修饰显著提升 Pd/石墨烯对1,2-丙二醇氧化反应的电催化活性,说明 Ag和Pd之间存在较强协同催化作用。%The electrochemical modification of graphene-supported Pd nanoparticles with a small amount of Ag and the electrooxidation of propane-1 ,2-diol on the Ag-modified Pd/graphene catalysts in alkaline solu-tion have been investigated to examine the effect of Ag modification on the activity of Pd/graphene catalyst.Instrumental and electrochemical characterizations show a partial coverage of the Pd nanoparticle surface by the Ag deposit.Although the Pd surface is decreased by the Ag deposit and Ag shows no cata-lytic activity for the electrooxidation of propane-1 ,2-diol,the Ag-modified Pd/graphene catalysts exhibit higher activity than that of Pd/graphene.For example,propane-1 ,2-diol oxidation on the Ag-modified Pd/graphene catalyst with a Ag∶Pd atomic ratio of 1∶38 shows an about 1.9 times higher peak current density than that on Pd/graphene catalyst.The result suggests that the Ag modification leads to a significant activ-ity enhancement for Pd/graphene catalyst,which is attributed to the synergistic effect between Ag and Pd.