The effect of electrolyte concentration on the catalytic activity of platinum for electrochemical oxygen reduction in phosphoric acid

✍ Scribed by H.R. Kunz; G.A. Gruver

• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 351 KB
• Volume: 23
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(78)85049-x

✦ Synopsis

An exptimental program was conducted ta determine the catalytic activity of platinum supported on carbon for the electrochemical reduction of oxygen in phosphoric acid as a function of temperature and electrolyte concentration. The Tafel slope was found to be approximately equal to 2.3 RT/F and independent of electrolyte concentration. The exchange current was found to decrease as the electrolyte concentration increased from 88 to IO5 wt%. The activation energy, however, was essentially independent of electrolyte concentration and approximately equal to 22 Kcal/mole. Because of the decrease in exchange current with increasing electrolyte concentration, the increased performance that can be obtained from a given quantity of platinum by increasing temperature is reduced at constant water vapor pressure above the electrolyte. in calculating the theoretical open circuit voltages used in this study.