1M KOH鹼性溶液中Ag-Cu、Ag-Co二元觸媒對氧還原反應之研究

Catalyst Activity of Ag-Cu and Ag-Co Films for Oxygen Reduction Reaction in 1 M Potassium Hydroxide Solution

張書維(S. W. Chang) ； 林景崎(J. C. Lin) ； 賴建銘(C. M. Lai) ； 朱恆慶(H. C. Chu)

《防蝕工程》 22卷4期 (2008/12) Pp. 277-285

https://doi.org/10.6376/JCCE.200812.0277

摘要

本研究以慢速極化掃描(Slow Scan Voltammetry, SSV)、鐵弗極化掃描(Tafel)、循環伏安法(Cyclic Voltammetry, CV)、能量散佈光譜儀(EDS)及X光光電子光譜儀(XPS)等方法，來探討利用濺鍍製作的Ag-Cu和Ag-Co薄膜在1M KOH鹼性溶液中成分比例與氧還原(Oxygen reduction reaction, ORR)活性之間的關係。由SSV實驗結果顯示，在Ag薄膜中添加第二元素(Cu、Co)會使Ag薄膜的氧還原活性增加，位於0V時純Ag的還原電流密度爲-0.461 mAcm^(-2)，Ag-50Cu爲-0.657 mAcm^(-2)，Ag-50Co 爲-1.320 mAcm^(-2)，第二元素的比例越高則氧還原活性越高，趨勢和Tafel所得的交換電流密度一致。由CV實驗結果發現Cu和Co的添加會使Ag的還原峰往陰極偏移。薄膜表面經XPS分析顯示，Ag-Cu表面生成Ag2O、Cu(OH)2和Cu2O等氧化物，Ag-Co表面生成Ag2O、Co3O4、CoO和Co(OH)2等化合物。由半定量分析結果相較，Ag-Cu中Ag氧化物的比例比Ag-Co來的更高，可能因此而造成較少的活性面積。

關鍵字

氧還原反應 ； 慢速極化掃瞄 ； 循環伏安法

並列摘要

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.

並列關鍵字

Oxygen reduction reaction ； Slow scan voltammetry ； Cyclic voltammetry