Simultaneous reactions on a rotating-disk electrode1

Multiple reactions at a rotating-disk electrode are modeled. The governing equations are used to generate a parameter which characterizes the effect of a side reaction on the limiting-current curve of a main reaction. Various predicted current-potential curves illustrate the importance of this parameter for copper deposition with simultaneous formation of dissolved hydrogen at a disk electrode rotating in a copper sulfate solution containing sulfuric acid. Distributions of current, potential, and surface concentration on the disk indicate that in some cases the main reaction can be below its limiting rate at the center of the disk while hydrogen gas bubbles may be formed near the edge. In addition, predicted and measured limiting-current curves for this system are compared. © 1977 Elsevier Sequoia S.A.