Coherence and coupling during oscillatory metal electrodissolution

The spatio–temporal behavior during periodic current oscillations in the Fe ∣ H2SO4 system is studied for a one-dimensional electrode surface. It is found that during the oscillatory response the electrode surface is never in the same state at the same time but the surface potential forms an accelerating front. The mode of communication between the individual regions of the reacting surface is explored by dividing the system into two identical coupled oscillators. The response is studied by either dividing the electrode surface with an insulating film of infinitesimal thickness or by a physical partition. The behavior of the coupled oscillators can be simple in-phase synchronization, k/n phase locking, out-of-phase locking or complex, depending on the length of the insulating film or the use of the partition and the applied potential. The results are compared with a model considering a simple coupling through the electrode potentials of the single oscillators. It is proposed that the coupling patterns can be attributed to the electrical coupling and the distribution of the frequency of the individual oscillators.