Beta Oscillations in the Electro-oxidation of Ethylene Glycol on Platinum

Oscillatory instabilities are ubiquitous in many electrocatalytic reactions. In the case of the electrocatalytic oxidation of small organic molecules, oscillating electrode potential and reaction current are very often found under different experimental conditions. Most of the experimental studies are devoted to C1 molecules such as formic acid and methanol, and very few reports concerning C2 compounds are available, in spite of their technological relevance as potential fuels. We report in this letter the observation of fast potential oscillations during the electro-oxidation of ethylene glycol on platinum and in alkaline media. Oscillations were studied under galvanostatic control, and oscillation frequencies as high as 16.8 Hz were observed. To the best of our knowledge, those potential oscillations are the fastest ones ever reported for the electro-oxidation of small organic molecules, and we named them beta oscillations in reference to the taxonomy employed to classify brain rhythms. Oscillations were observed at different temperatures, and the system's dynamics was found to be rather insensitive to temperature, in contrast to that observed under non-oscillatory regime.