Electrochemical oscillations during the oxidation of 2-(dimethylamino)ethanethiol

Abstract

• The electrochemical oxidation of DMAET led to oscillations in current and potential. • Electrochemical impedance spectroscopy was used to confirm the presence of negative differential resistance. • High frequency oscillations were observed under potentiostatic conditions. • The system supports complexity in the form of bursting and mixed-mode oscillations. This paper describes the electrochemical oxidation of 2-(dimethylamino)ethanethiol (DMAET), a known hydrolysis product of V-type nerve agents, which can be used to mimic the behavior of chemical warfare agents. Interestingly, during its oxidation, two distinct regions of dynamic (i.e., oscillatory) behavior were uncovered. Mechanistic investigation using electrochemical impedance spectroscopy (EIS) lead to the discovery that one of the oscillatory regions was driven by the presence of negative differential resistance (NDR) and that the occurrence of the other was dependent on the concentration of supporting electrolyte. EIS measurements indicated that the DMAET electrochemical oscillator belongs to the HN-NDR class of oscillators, which was supported by the presence of sustained oscillations in both current (under potentiostatic conditions) and potential (under galvanostatic conditions). Furthermore, the oxidation of DMAET on platinum electrodes resulted in rich dynamical behavior in the form of complex bursting phenomena.