Evolution of spatiotemporal patterns during the electrodissolution of metals: Experiments and simulations.

Spatiotemporal patterns including accelerating fronts, rotating waves, and homogeneous oscillations evolve during the electrodissolution of metals like cobalt and iron that exhibit passivity under potentiostatic control. The nature of the patterns is determined by long-range (nonlocal) coupling through the electric field which in turn is influenced by the geometry of the electrochemical cell, the applied potential, and the conductivity of the electrolyte. A two-variable model in a three-dimensional geometry is presented which is able to simulate the essential features of the experimental system.

Identification of the intermittency-I route to chaos in oscillating CO oxidation on zeolite-supported Pd.

For the oscillating oxidation of CO on a zeolite-supported palladium catalyst the transition to chaos could be observed in a very narrow region of the CO concentration in the feed. The reaction was carried out under the conditions of a continuous stirred tank reactor. A careful choice of the method for time series analysis led to the unambiguous identification of the intermittency-I route to chaos in the catalytic system despite the rather limited number of data points which can be acquired under normal pressure conditions.