New directions and challenges in electrochemistry -: Spontaneous formation of spatiotemporal patterns at the electrode | electrolyte interface

Practically every electrochemical reaction exhibits temporal instabilities, such as bistable reaction rates or spontaneous oscillations of current or potential, in some range of the external parameters. In the presence of transport processes, or more generally of a mechanism that mediates a spatial coupling among different sites, temporal instabilities are usually accompanied by spatial symmetry breaking. This article reviews the different ways in which reaction term and spatial coupling can interact in electrochemical systems, and it summarizes the kind of patterns that may arise under different experimental conditions. Emphasis is placed on establishing a connection between eletrochemical mechanisms and prototype models in nonlinear dynamics to facilitate a classification of the different phenomena. This presentation seeks to be helpful in exploring possibilities to utilize nonlinear behaviors in technological applications; some perspectives are discussed at the end. (C) 2001 Elsevier Science B.V. All rights reserved.