Phosphate oxidation on boron doped diamond electrode
L. Hliwa1, L.M. Ghallabi1, M. Azzi1*, N. Saib1,
1 Equipe d’Electrochimie et Chimie de l’Environnement, Laboratoire Interface Matériaux Environnement,
Facultés des Sciences Ain Chock. B.P 5366, Maârif Casablanca Morocco
2 Laboratoire d’Electrochimie et de Physico-chimie des Matériaux et Interfaces UMR 5631 INPG - CNRS, ENSEEG,
B.P 75, 38402 Saint Martin d’Hères Cedex, France
* Corresponding author. E-mail: email@example.com
Received: 20 May 2009; revised version accepted: 19 July 2010
The electrochemical study shows that phosphate ions oxidation on Boron Doped Diamond (BDD) occurs before oxygen evolution in aqueous mild. The reaction rate is enhanced in a basic solution. With voltametric studies it is shown that oxidation current is linearly dependent on phosphate ions concentration and potential scan rate. The electro-chemical mechanism is very complex and involves several steps with adsorbed species and radicals. The electrolysis at fixed potential leads to peroxodiphosphate species formation in solution. The complexity of electrochemical mechanism is confirmed by electrochemical impedance spectroscopy (EIS) study. EIS measurements demonstrate also that BDD electrode-electrolyte behavior is compatible to p-type semiconductor with 1.49 V as plate band potential.
Keywords: BDD - phosphate oxidation; Peroxodiphosphate ion; Voltametric study; Electrolysis; EIS measurements.