Modelling of spatiotemporal patterns during metal electrodissolution in a cell with a point reference electrode

A model for the simulation of experimentally observed spatiotemporal patter ns in the bistable and oscillatory regions during the electrodissolution of metals under potentiostatic control is presented. A two-dimensional geomet ry was used with a point-like reference electrode located in the electrolyt e between the working and the counter electrodes. The dynamical variables o f the model are the potential drop across the electric double layer and the proton concentration near the working electrode surface. The effects of ch anging parameter values such as cell geometry, electrolyte conductivity, an d double layer capacitance on time series and spatial patterns are presente d. In a bistable system the reference electrode position influences both th e front behavior and also the structure (uniform or nonuniform) of the stea dy state. In the oscillatory region the direction of the passivation wave c an be changed by changes in the location of the reference electrode. An inc rease in electrode length can change a periodic oscillation with almost uni form spatial distribution to a chaotic behavior with nonuniform pattern.