Spectroscopic Studies of the Glycerol Electro-Oxidation on Polycrystalline Au and Pt Surfaces in Acidic and Alkaline Media

The electro-oxidation of glycerol on Au and Pt was studied in acid and alkaline media. The reaction intermediates and products formed were determined by in situ Fourier transform infrared (FTIR) spectroscopy. The experimental FTIR spectra measured on Au and Pt in acid and alkaline media were compared with the standard ones for the identification of the oxidation products. For Au, the oxidation reaction is highly dependent on the solution pH. In alkaline medium, dihydroxyacetone, tartronic acid, mesoxalic acid, glyoxylic acid, and carbon dioxide are formed while in acidic medium tartronic acid, formic acid, and carbon dioxide are formed. However, the oxidation of glycerol on Pt leads to the formation of tartronic acid, glycolic acid, glyoxylic acid, formic acid, and carbon dioxide, independent of the solution pH. For both electrode materials, Pt and Au, carbon dioxide is detected indicating the possible breaking of the C-C-C bonds. Clearly, the glycerol oxidation pathways can be controlled by the nature of the electrode material and solution pH. Furthermore, glycerol is a typical compound that has potentiality to produce electricity when feed a fuel cell while many chemicals with commercial interest are concomitantly formed.