Electrochemical and in situ FTIR studies of ethanol adsorption and oxidation on gold single crystal electrodes in alkaline media

Abstract

The electrooxidation of ethanol on Au(1 1 1), Au(1 0 0), Au(1 1 0) and Au(2 1 0) single crystal electrodes as well as on Au polycrystalline electrode have been investigated in alkaline media using cyclic voltammetry (CV) and in situ Fourier transform infrared reflectance (FTIR) spectroscopy. It has been found that the catalytic activity for the electrooxidation of ethanol in the low potential region decreases in the following order: Au(1 1 0) > Au(2 1 0) > Au(1 0 0) > Au(poly) > Au(1 1 1). This suggests that the defect sites on the Au surface dominate the electrooxidation of ethanol. On the other hand, both the adsorbed OH and the potential of zero charge on the surface play an important role in the ethanol oxidation reaction. The FTIR spectroscopy measurements show that the main reaction product of ethanol oxidation reaction in the alkaline media is acetate. This result indicates that the reaction product on gold is independent of the electrode’s orientation.