There is an increasingly interest in the use of small organic molecules in the interconversion
between chemical and electrical energies. Among the strategies to improve the processes of
yielding electrical energy in fuel cells and the production of clear hydrogen in electrochemical
reform is the use of kinetic instabilities to improve the conversion and selectivity. Herein we
report on the electrocatalytic efficiency of the oxidation of ethylene glycol, glycerol, and
glucose, under regular and oscillatory regimes, on polycrystalline platinum, in sulfuric acid
aqueous solution, and at 25 oC. Despite the high overpotentials for the electro-oxidation of these
molecules, the electrochemical activity along quasi-stationary potentio/gavanostatic
experiments evidenced that, in all cases, relatively lower potential values, and thus higher
activity, are reached during oscillations. Noticeably higher power densities for the electrooxidation of ethylene glycol and glycerol under oscillatory regime in a hypothetical direct liquid
fuel cell. The use of identical experimental conditions of that of our previous study[J. Phys.
Chem. C 120 (2016) 22365] allowed at discussing some universal trends for seven small
organic molecules. We compile the results in terms of the peak current, the maximum poisoning
rate found along the oscillations, and the oscillation frequency. The three parameters were
found to decrease in the order: formaldehyde > formic acid > methanol > ethanol > ethylene
glycol > glycerol > glucose. In addition, we discussed the increase of the voltammetric current
with the self-organized poisoning rate and reinforce the trend that high electrocatalytic activity
implies high susceptibility to surface poisoning for this set of species. Finally, the analysis done
for all species (formic acid, formaldehyde, methanol, ethylene glycol, ethanol, glycerol, and
glucose) adds to the available thermodynamic data and is a benchmark against which the
activities under oscillatory regime at 25 oC may be compared or assessed. This point of
reference permits to explore further experimental conditions that are relevant for energy-related
devices, including the conversion of chemical into electrical energy and the electrochemical
reform to produce clean hydrogen in electrolyzers.
Electrocatalytic Efficiency of the Oxidation of Ethylene glycol, Glycerol, and Glucose under Oscillatory Regime
