Oxalic acid (OA) represents one of the proposed metabolites of the anodic oxidation of more complex organic molecules; in spite of its simple structure, its mineralization is strongly dependent on the nature of the electrode material at which the process is carried out. Sargysian and Vasil’ev [1] pointed out such dependence, investigating the kinetic behavior of OA at different metal electrodes (Rh, Pd, Os, Ir, Pt and Au), at a DSA-type anode (RuO2-TiO2) and at glassy carbon. Their conclusions, also in agreement with our recent results on the topic [2], highlighted the important role played by the anion adsorption step, claiming that OA is oxidized with increasing difficulty at electrode materials having higher oxygen affinity. In the present work, the analysis of the dependence of the OA electroxidation on the nature of the electrode material has been extended to highly conductive, boron-doped diamond (BDD) electrodes, with either oxygen and fluorine at their surfaces. At variance with glassy carbon, BDD-based electrodes should permit elucidating the aspects of the OA kinetic behavior at carbonaceous materials, without exhibiting the mechanical and chemical limitations of graphite and GC. Moreover, the different hydrophobic/hydrophilic character of the BDD and F-BDD electrode surfaces, which necessarily reflect in the structure of the electrode/electrolyte double-layer, will be also taken into consideration.
Kinetic mechanism of the electroxidation of oxalic acid at different electrode materials
FERRO, Sergio;MARTINEZ, Carlos Alberto;DE BATTISTI, Achille
2004
Abstract
Oxalic acid (OA) represents one of the proposed metabolites of the anodic oxidation of more complex organic molecules; in spite of its simple structure, its mineralization is strongly dependent on the nature of the electrode material at which the process is carried out. Sargysian and Vasil’ev [1] pointed out such dependence, investigating the kinetic behavior of OA at different metal electrodes (Rh, Pd, Os, Ir, Pt and Au), at a DSA-type anode (RuO2-TiO2) and at glassy carbon. Their conclusions, also in agreement with our recent results on the topic [2], highlighted the important role played by the anion adsorption step, claiming that OA is oxidized with increasing difficulty at electrode materials having higher oxygen affinity. In the present work, the analysis of the dependence of the OA electroxidation on the nature of the electrode material has been extended to highly conductive, boron-doped diamond (BDD) electrodes, with either oxygen and fluorine at their surfaces. At variance with glassy carbon, BDD-based electrodes should permit elucidating the aspects of the OA kinetic behavior at carbonaceous materials, without exhibiting the mechanical and chemical limitations of graphite and GC. Moreover, the different hydrophobic/hydrophilic character of the BDD and F-BDD electrode surfaces, which necessarily reflect in the structure of the electrode/electrolyte double-layer, will be also taken into consideration.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
