Bistability and excitability in the electrochemical oxidation of ethanol

Results are presented from experiments on the oxidation of ethanol at a Pt electrode in acid solution. The experiments were conducted under conditions of constant current. The results show that the oxidation process exhibits a bistable response in which two different branches of steady-state potential values exist under the same conditions. Measurements also reveal that the process exhibits excitability: a relatively small change or perturbation causes the potential to undergo a large and long excursion before it returns to its steady-state value. Oscillations are also examined with a focus on the correlation between characteristics of the oscillations and the length of time the system is allowed to relax. Bistability is discussed in terms of a model previously used to describe multistability in the oxidation of methanol. Comparisons are made between the nonlinear behavior observed in the oxidation of ethanol and that observed in the oxidation of methanol. (C) 1999 Elsevier Science Ltd. All rights reserved.