Oxygen Reduction on Silver in 6.5M Caustic Soda Solution

The cathodic reduction of oxygen in 6.5M membrane-grade caustic soda solution has been studied experimentally at a silver rotating disk electrode at 25~ The results can be approximated by the parallel mechanism for oxygen reduction with catalytic decomposition of peroxide. Further analysis of this mechanism indicates that the sequential process with catalytic decomposition of peroxide predominates over the direct 4e- process. Direct application of the sequential mechanism to the data indicates that the latter mechanism with catalytic decomposition of peroxide much more accurately reflects the experimental results. The relevant kinetic parameters are calculated on the basis of the mechanisms presented.