Ethanol electro-oxidation on platinum in alkaline media

Abstract

The electrochemical oxidation of ethanol as well as its irreversible adsorption on platinum single crystal electrodes has been studied in an alkaline solution. In addition, the adsorbed species in the ethanol oxidation reaction were also studied by means of surface enhanced Raman spectroscopy (SERS) on a platinum film electrode. It was found that the oxidation of ethanol is very sensitive to the electrode surface structure: a higher concentration of low-coordination sites increases the current, lowers the overpotential required and lowers the deactivation rate. Furthermore, the terrace length also affects the amounts and the nature of the adsorbed species: on Pt (110), only CO_ad was observed, whereas adsorbed CH_x could only be found on electrode surfaces with (111) terrace sites. Based on the results here, a model for the ethanol electro-oxidation reaction in alkaline media is presented, and the differences with the same reaction in acidic media are pointed out.