Faradaic rectification studies of two electron charge transfer redox couples at the metal (solid) interface

✍ Scribed by H.P. Agarwal; S. Qureshi

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 321 KB
• Volume: 21
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(76)85132-8

✦ Synopsis

Faradaic rectification studies of the two electron charge transfer processes, cationic and anionic redox couples, have been carried out. The mechanism of the iodide-iodine reaction through single charge transfer comprises the following steps, of which reaction (b) is the slowest and controls the rate of overall reaction. I-= L. + e (4 I _111< + I-= Iz.d. + r @) I la_ + I-= I-3' (c) Chemical The values of the transfer coefficient and rate constant are obtained for the second step, which is rate determining in both the directions. The values of the parameters obtained when the concentration of the electrochemical species (IJ is much less in comparison to that of iodide, are ~1, = m, = O-5 and k." of the order of 5 x 10m5 cm/s. The parameters for the iodideiodine reaction, using 1.0 M KNO, as supporting electrolyte. are CI, = O-49, a, = 0.51 and k,O of the order of 5 x 10e3 cm/s. For the stannousstannic reaction either of the two steps appears to be rate determining in both directions and the values of the parameters obtained are a, = 0.48, a, = 0.52 and k,O = 2.1 x 10m3 cm/s.