Electroxidation of oxalic acid at different electrode materials

Oxalic acid is one of the proposed metabolites of the anodic oxidation of more complex organic molecules. In spite of its simple structure, its mineralization strongly depends on the nature of the electrode material at which the process is carried out. Sargisyan and Vasil’ev (Elektrokhimiya 18:845, 1982) pointed out such dependence, investigating the kinetic behavior of OA at different metal (Rh, Pd, Os, Ir, Pt and Au), at dimensionally stable anodes (RuO2–TiO2) and at glassy carbon (GC) electrodes. Their conclusions highlighted the important role played by the organic anion adsorption step, claiming that OA is oxidized with increasing difficulty at electrode materials having higher oxygen affinity. More recently, these assumptions have been supported by data on OA oxidation at high anodic potentials (Martínez-Huitle et al., Electrochim Acta 49:4027, 2004). To further enrich the picture, in the present paper, kinetic investigations were carried out at different mixed-oxides, Pt, GC and highly conductive, boron-doped diamond (BDD) electrodes, with either oxygen or fluorine at their surface.