Further Insights on the Electrooxidation of Ethanol by in situ IRRAS in D2O Electrolytes

摘要

The electrooxidation of small molecules such as methanol and ethanol is a topic of great interest for the scientific community. In part, this interest is because these molecules are attractive models for the study of electrochemical oxidation reactions. In recent times, however, the interest about the electrooxidation of such small organic molecules, mostly methanol and ethanol, is because they are considered as ideal energy carriers for low temperature fuel cells [1]. A number of studies devoted to understanding ethanol electrooxidation pathway have appeared in recent times. In general, these studies have been conducted with spectroelectrochemical devices such as Infrared cells in different configurations such as Infrared Reflection Adsorption Spectroscopy (IRRAS) or ATR or Differential electrochemical mass spectrometry (DEMS). These studies report the formation of acetyl-like species during the electrooxidation of ethanol and suggest that this species is the precursor for the C-C scission of ethanol. However, the correct identification of acetyl species by infrared spectroscopy in H2O containing electrolytes is not straightforward since both species have vibrational frequency modes active within the same frequency region. In order to overcome this issue, we have conducted in situ IRRAS studies of the electrooxidation of ethanol (and acetaldehyde) in D2O containing electrolytes.