Turing patterns and electrochemical SYSTEMS

Experimental verification of this principle could be achieved by the technique of surface plasmon microscopy by which the lateral distribution of the electrode potential at a thin film can be monitored [11]. The experiments were performed with the reduction of periodate (I04 ) in the presence of camphor on a thin, preferentially (11 l)-oriented Au film [12]. Adsorbed camphor exhibits two first-order phase transitions upon variation of the electrode potential leading to the required S-shaped current-voltage characteristics. (The addition of perchlorate to the 

FIGURE 8.1. Principle of the mechanism underlying the formation of electrochemical Turing patterns [5]. (See color insert.) 

Apart from the stationary potential patterns just discussed, propagating potential waves under the influence of global (nonlocal) coupling via migration of ions in the electric field are much more readily realized in electrochemical systems [5]. These effects may be most conveniently studied with quasi-one-dimensional systems, that is, ring electrodes where the potential can be recorded at various locations. One example is concerned with the potentiostatic electrochemical oxidation of formic acid on a platinum ring electrode under bistable conditions, as 

FIGURE 8.3. Schematic sketch of the electrode arrangement for studying remote triggering of potential waves in an electrochemical system [44]. 

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