Silver electrochemical reaction orders

As an example of the determination of electrochemical reaction orders, we consider the deposition of silver from an aqueous solution containing cyanide. The latter forms various complexes with silver ions, such as AgCN, Ag(CN) ", Ag(CN)3. Therefore, in the bulk of the solution reactions of the type ... 

Then, with z— 1, n = 1, and v n- = the following electrochemical reaction orders are determined for the silver electrode ... 

Similar size effects have been observed in some other electrochemical systems, but by far not in all of them. At platinized platinum, the rate of hydrogen ionization and evolution is approximately an order of magnitude lower than at smooth platinum. Yet in the literature, examples can be found where such a size effect is absent or where it is in the opposite direction. In cathodic oxygen reduction at platinum and at silver, there is little difference in the reaction rates between smooth and disperse electrodes. In methanol oxidation at nickel electrodes in alkaline solution, the reaction rate increases markedly with increasing degree of dispersion of the nickel powders. Such size effects have been reported in many papers and were the subject of reviews (Kinoshita, 1982 Mukerjee, 1990). 

These few examples of the application of solid state galvanic cells in the field of solid state reactions can only present a very limited view of this important area of solid state science. The examples were chosen primarily in order to demonstrate the principles according to which solid state research in thermodynamics and kinetics should be conducted with the use of electrochemical tools and methods. Such measurements are only possible because of the existence of suitable solid electrolytes. The most important of these are Zr02(-f CaO) and Th02(+Y2 03) for oxygen, silver halides and Ag4Rbl5 for silver, copper halides for copper, some glasses in which certain ions are dissolved, and p — Al2 03(-hNaO) for sodium. 

---