1M KOH鹼性溶液中Ag-Cu、Ag-Co二元觸媒對氧還原反應之研究

Catalytic activity of Ag-Cu and Ag-Co films for oxygen reduction reaction (ORR) in KOH electrolyte was investigated in this work. The dependence of the catalytic activity on the film composition was explored by means of the electrochemical techniques such as slow scan voltammetry (SSV), Tafel plot, cyclic voltammetry (CV) with the aid of surface analysis of the films by X-ray photoelectron spectroscopy(XPS). Resulting from SSV, it was found that the catalytic activity of Ag-Cu and Ag-Co films for ORR increases with increasing the concentration of Cu and Co in the films. At 0V, the reduction current of Ag is -0.461 mAcm^(-2). The current of reduction is higher for Ag-50Co (-1.320 mAcm^(-2)) than Ag-50Cu (-0.657 mAcm^(-2)). According to cyclic voltammogram, the reduction peak of silver oxide is at lower potential for the Ag-Cu and Ag-Co films compared to pure Ag film. Analysis of XPS indicated that the catalytic activity of Ag-Cu and Ag-Co films decreases with increasing the percentage of silver oxide in the composition of the surface film. Higher percentage of silver oxide in Ag-Cu than Ag-Co leads to lower activity for the ORR.