Cr(III) oxidation with lead dioxide-based anodes

A procedure for preparing PbO2-based electrodes with a titanium substrate is proposed. A platinum underlayer is first deposited on Ti by metal organic chemical vapor deposition (MOCVD), followed by the electrodeposition of the PbO2 layer. The prepared Ti/Pt/PbO2 anodes were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) before being used for oxidation of Cr(III) in sulphuric acid. The current efficiency was determined for that electrodes and the results were compared with those obtained with Pb/PbO2 and Ebonex [reg] /PbO2 electrodes with different pH conditions. The Ti/Pt/PbO2 were found to have a very good electrochemical behaviour (current efficiency: phi=0.93 for pH 2), and may be used as dimensionally stable anodes for the oxidation of Cr(III)