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Free keywords:
Bistable Semiconductor System; Pattern-Formation; Electrochemical Systems; Ring Electrode; Sulfuric-Acid; Potential Patterns; Anodic-Dissolution; Wave Oscillations; Iron; Oxidation
Abstract:
Pattern formation in electrochemical systems depends sensitively on the relative arrangement of the electrodes. We present simulations of spatiotemporal patterns during the electrodissolution of a metal disk electrode in which the reference electrode is located on the axis of the disk and close to the metal working electrode. This geometry introduces a strong but asymmetric negative feedback, which tends to destabilize the homogeneous potential distribution. We demonstrate that the feedback gives rise to a variety of complex antiphase-type patterns. Some of these patterns have been observed in experiments; others present novel manifestations of dynamic instabilities in electrochemical systems.