An in situ Fourier transform infrared spectroelectrochemical study on ethanol electrooxidation on Pd in alkaline solution

The mechanism of ethanol electrooxidation on a palladium electrode in alkaline solution (from 0.01 to 5 M NaOH) has been investigated by cyclic voltammetry and in situ Fourier transform infrared spectroelectrochemistry. The electrode performance has been found to depend on the pH of the fuel solution. The best performance was observed in 1 M NaOH solution (pH = 14), while the electrochemical activity decreased by either increasing or decreasing the NaOH concentration. In situ FTIR spectroscopic measurements showed the main oxidation product to be sodium acetate at NaOH concentrations higher than 0.5 M. The C–C bond cleavage of ethanol, put in evidence by the formation of CO2, occurred at pH values ≤13. In these conditions, however, the catalytic activity for ethanol oxidation was quite low. No CO formation was detected along the oxidation of ethanol by FTIR spectroscopy.