Tuning oscillatory time-series evolution by Pt(111)-OHad stabilization

Direct Liquid Fuel Cells—The Influence of Temperature and Dynamic Instabilities

“…In general, regardless of the temperature, we observed only one type of oscillatory pattern: simple and quasi -sinusoidal. ,,− Unlike half-cell studies with massive Pt electrodes, , the oscillations exhibited in Figure are much more robust over time largely because of the high surface area of gas diffusion electrodes. A slow drift, responsible for driving the system through different oscillatory patterns until the point where oscillations are no longer sustainable, , although, inevitably, occurs during the oscillatory operation of the DMFC, it has an insignificant effect on its overall response and the autonomous dynamics presented in Figure can last for hours without significant changes in their profiles.…”

“…It is important to highlight that the spontaneous emergence of oscillations along an electrochemical reaction allows us to access information that is inaccessible in conventional voltammetry or steady-state chronopotentiometry/amperometry. ,,,,− ,, For example, if we evaluate the oscillatory frequency, ω H or ω galv , alongside with the maximum poisoning rate during an oscillatory cycle, (d E /d t ) max , it is noted that although methanol has a much faster dynamic than ethanol and formic acid, the latter has the highest d E /d t value (Figure S2 on the Supporting Information presents d E /d t versus E curves used to estimate (d E /d t ) max ). This fact reinforces that from the three molecules, formic acid in an oscillatory regime has the greatest appeal in terms of efficiency gains ,, because during each cycle, the potential remains longer at low potentials and it is only in a short time interval that reaches its maximum and returns to its minimum (Figure ).…”

Direct Liquid Fuel Cells – The Influence of Temperature and Dynamic Instabilities

“…19,31,[35][36][37] Unlike half-cell studies with massive Pt electrodes, 31,37 the oscillations exhibited in Figure 2 are much more robust over time, largely due to the high surface area of gas diffusion electrodes. A slow drift, responsible for driving the system through different oscillatory patterns until the point where oscillations are no longer sustainable, 31,56 although, inevitably, occurs during the oscillatory operation of the DMFC, it has an insignificant effect on its overall response and the autonomous dynamics presented in Figure 2 can last for hours without significant changes in their profiles.…”

“…It is important to highlight that the spontaneous emergence of oscillations along an electrochemical reaction allows us to access information that is inaccessible in conventional voltammetry or steady-state chronopotentio/amperometry. 13,30,34,35,[37][38][39]56,57 For example, if we evaluate the oscillatory frequency, ωH or ωgalv, alongside with the maximum poisoning rate during an oscillatory cycle, (dE/dt)max, it is noted that although methanol has a much faster dynamic than ethanol and formic acid, the latter has the highest dE/dt value ( Figure S2 on the Supplementary Information presents dE/dt versus E curves used to estimate (dE/dt)max). This fact reinforces that, from the three molecules, formic acid in an oscillatory regime has the greatest appeal in terms of efficiency gains, 13,18,19 because during each cycle, the potential remains longer at low potentials, and it is only in a short time interval that reaches its maximum and returns to its minimum ( Figure 5).…”

Electrochemical Oscillations (Named Oscillations H and K) during H2O2 Reduction on Pt Electrodes Induced by a Local pH Increase at the Electrode Surface

“…The study of oscillatory instability has also received attention because it provides a deeper understanding of complex electrochemical reactions, such as the oxidation of C1 organic molecules 8,9 and intermolecular interactions between electroactive species and adsorbates. [10][11][12][13] Interestingly, these studies have even provided valuable information that has led to improvements in the discharge capacity of lithium-oxygen batteries. 14 The N-shaped negative differential resistance (N-NDR) plays a crucial role in the positive feedback mechanism for typical electrochemical oscillators: the N-NDR oscillator and the "hidden" N-NDR (HN-NDR) oscillator.…”