| Popis: |
It is shown experimentally that mixed-mode oscillations may be observed in the peroxodisulfate reduction on platinum and gold rotating disk electrodes, in addition to previously reported monoperiodic (relaxation) oscillations. If account is made for the internal drift of the system, the typical features of the mixed-mode oscillations are in good agreement with the predictions of a model which combines the negative faradaic impedance characteristics with a treatment of the mass transport that goes beyond the stationary diffusion layer approximation. Although the actual observation of mixed-mode oscillations requires a pretreatment procedure the precise effect of which is poorly understood, these results may be interpreted as evidence for the importance of slow mass transport in the explanation of multiperiodic and chaotic electrochemical oscillations. |
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