Micro- and nanostructured TiO2 substrate: Influence on the electrocatalytic properties of manganese oxide based electrodes

Abstract Mixed ruthenium and manganese oxides electrodes (1:1 molar ratio) have been prepared by spin-coating deposition and subsequent thermal decomposition of a thin film on a titanium support. To improve both stability and adhesion of the coating, either micro- or nanomodification of the titanium surface has been investigated. The micro-modified support has been obtained by etching of the titanium foil with hydrofluoric acid (HF) while the modification at a nanoscale has been obtained by anodization of the titanium foil in a glycerol medium containing fluoride. In this last case, formation of a highly ordered nanotubular structure of titania was verified. The prepared electrodes have been characterized in terms of morphological and chemical properties by scanning electron microscopy (SEM) and Energy Dispersive X-ray Analysis (EDX). Their electrochemical behavior has been studied by polarization curves and cyclic voltammetry tests. Finally, the oxidation ability in the electrogeneration of inorganic chlorinated species and in the degradation of aqueous solutions containing the Reactive Blue 4 dye (RB4) as the model compound has been evaluated. To this aim, galvanostatic experiments have been conducted in a membrane-free reactor. The encouraging results support the need to further study highly modified electrodes based on mixed ruthenium and manganese oxide for their use in anodic oxidation process with special attention to avoid uneven distribution of metal oxides.