Large disk electrodes of Ti/TiO2-nanotubes/PbO2 for environmental applications

Abstract

Large disk electrodes of Ti/TiO₂-nanotubes/PbO₂ (65 cm² of geometrical area) were successfully synthesized by anodization and electrodeposition procedures. Characterization of anodes was performed by SEM, EDS, AFM and electrochemical measurements, aiming towards environmental applications. PbO₂, an electrocatalytic material, promotes the production of strong oxidising species (hydroxyl radicals) that can be used for decontamination. Electrochemical treatment of synthetic dye effluent (2 L) containing 250 mg L⁻¹ of Acid Blue 113 dye (AB 113) was performed using a disk Ti/TiO₂-nanotubes/PbO₂ anode and an electrochemical flow cell. More than 85% of organic matter was removed by applying current densities of 20, 40 and 60 mA cm⁻². Moreover, colour decay achieved values of 60%, 90% and 100%, depending on the applied current density. Alternatively, this study allows us to understand how nanomaterials have prevented the corrosion phenomena on the anode surface (Pb²⁺ pollution) due to the homogeneous migration of PbO₂ within the TiO₂ nanotubes previously formed on the Ti support.