In-situ surface-enhanced Raman spectroscopic investigation on ethanol electrooxidation in different media

Electrochemical voltametric methods and in-situ electrochemical surface-enhanced Raman spectroscopy (SERS) were used to investigate the electrooxidation behavior of ethanol in different media on a roughened platinum electrode. It was found that ethanol could dissociate spontaneously to produce strongly adsorbed intermediate, CO, in acidic, neutral, and alkaline media on the roughened platinum electrode. The complete oxidation potential of COad on the roughened platinum electrode was negatively shifted about 0.300 V in the alkaline medium (0.20 V) compared with that in the acidic and neutral media (0.50 V). The positive oxidation peak potential of ethanol was negatively shifted about 0.85 V in the alkaline medium (-0.20 V) than that in the acidic medium (0.65 V). By comparing the oxidation current and the peak potential, it was found that the electrocatalytic activity of roughened platinum electrode for ethanol and CO oxidation in the alkaline medium was higher than in acidic and neutral media. The results suggested that ethanol was oxidized to CO2 on the roughened platinum electrode via parallel reaction mechanism in acidic, neutral or alkaline media.