银修饰对钯/石墨烯电催化活性的促进效果

Promoting Effect of Ag Modification on the Electrocatalytic Activity of Pd/Graphene

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-I, 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 activity enhancement for Pd/graphene catalyst, which is attributed to the synergistic effect between Ag and Pd.