Oxygen Reduction on Silver Low-Index Single-Crystal Surfaces in Alkaline Solution:  Rotating Ring DiskAg( h kl ) Studies

• Published in: The journal of physical chemistry. B Vol. 110; no. 10; pp. 4735 - 4741
• Main Authors: Blizanac, B. B, Ross, P. N, Marković, N. M
• Format: Journal Article
• Language: English
• Published: American Chemical Society 16.03.2006
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp056050d

The rotating ring disk method is applied to investigate the oxygen reduction reaction on Ag single-crystal surfaces in alkaline solution over the temperature range 293−333 K. At all temperatures, the oxygen reduction reaction proceeds through the 4e- reaction pathway with a very small (≈0.5−2%) peroxide formation. At the same temperature and overpotentials, the kinetics of the ORR always increases in the order (100) ≤ (111) < (110), indicating that the reaction is structure-sensitive. We present an interpretation of the structure sensitivity based on the supposition that it arises from (i) a potential-dependent adsorption of spectator hydroxyl ions and (ii) variations in activation energies, which are determined by the O2 adsorption on Ag single-crystal surfaces covered by adsorbed oxygenated species.