The electrochemistry of silver in koh at elevated temperatures—III. Potentiostatic study

✍ Scribed by Bruce G. Pound; Digby D. Macdonald; John W. Tomlinson

• Publisher: Elsevier Science
• Year: 1980
• Tongue: English
• Weight: 381 KB
• Volume: 25
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(80)87136-2

✦ Synopsis

The electrochemistry ofpolycrystalline silver in 1 mol kg-' KOH at tempera'tures between 295 K and 478 K has been studied using potentiostatic polarization. At potentials corresponding to silver dissolution and to the early stages of Ag,O formation, the transient current data at all the temperatures studied exhibit regions that are linearly dependent on the inverse square root of time. This dependence indicates mass transport to be a rate limiting step in these processes. Log (steady-state current) us potential data show that at all temperatures silver undergoes an active-to-passive transition. However, the potential of the transition shifts to less positive values and the passive current increases with increasing temperature. In the region of formation of surface oxide phases, the transients exhibit maxima due to nucleation and growth phenomena. The effect of temperature on the transients is similar to the efliit of overpotential; in both cases, the time taken to reach the maximum current decreases.