Analytical Sciences

Abstract − Analytical Sciences, 22(10), 1315 (2006).

Evaluation of the Oxygen Reduction Activities of Rare-Earth Oxide-supported Silver Catalysts Using a Channel Flow Double Electrode
Masayuki ITAGAKI,* Yasuhiro FUJIMURA,* Isao SHITANDA,* Kunihiro WATANABE,* and Toshinori HACHIYA**
*Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba 278-8510, Japan
**Asahi Kasei Chemicals Corporation, 7-4319, Asahi-machi, Nobeoka, Miyazaki 882-0847, Japan
The channel flow double electrode (CFDE) was used for the evaluation of the oxygen reduction activities in alkaline solution of rare-earth oxide-supported silver catalysts. The CFDE cell was modified for the experiment using the powder catalyst as a working electrode. In the present experiment, the silver electrode was supported with CeO2 in order to improve the performance of the oxygen reduction. The detecting electrode current for HO2- emitted from the working electrode was recorded simultaneously with the measurement of the i-E curve of each working electrode. Moreover, the average number of charge transfers n was calculated from the working and detecting electrode currents. The value of n for the oxygen reduction was approximately 4 for silver electrode supported with rare-earth oxide, compared with the n value of pure silver that was smaller than 4. On the basis of these results, the mechanisms of oxygen reduction on these electrodes and role of the rare-earth oxide in alkaline solution were discussed.