Pt-Ru/C催化剂在甲醇电氧化过程中的组成和结构变化

本文研究了Pt-Ru/C催化剂在甲醇电催化氧化过程中组成和结构的变化。结果表明:在扫描初期,Pt-Ru催化剂的表面处于富Ru状态,Pt-Ru催化剂显示出良好的协同效应,峰电位较低,峰电流密度也较小。随着扫描圈数的增加(1~35圈),催化剂表面Ru原子逐渐溶解,Pt-Ru协同效应减弱,峰电位逐渐增大;同时,随着Ru的溶解,催化剂表面Pt原子含量的增加,催化剂对甲醇氧化的峰电流密度逐渐增大。继续增加扫描圈数(36~80圈),催化剂表面Ru原子含量趋于稳定,但Pt原子发生表面重组,粒子粒径增大,从而导致催化剂对甲醇电氧化性能下降。

Changes of Composition and Structure of Pt-Ru/C Catalyst in the Methanol Electro-Oxidation Process

In this paper, the changes in the composition and structure of Pt-Ru/C catalyst in the course of the methanol electrooxidation were studied by cyclic voltammetry (CV), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the surface layer of Pt-Ru/C catalyst was Ru-rich structure and possessed excellent synergistic effect for methanol electrocoxidation in the early stage of CV scan. While the cycling number increased from 1 to 35, the peak potential of methanol oxidation gradually shifted to the high potential, which was attributed to decrease of the synergistic effect owing to the dissolution of Ru atoms in the surface of Pt-Ru/C catalyst. When further increasing the cycling number to 36~80, the Ru content tends to be stable. However, the particles size of Pt-Ru nanoparticles gradually increased due to the moving and relocation of surface Pt atom, which resulted in the decrease of electrocatalytical activity of the catalyst for methanol oxidation.