Influence of surface roughening of Titanium substrate in the electrochemical activity of Manganese oxide thin film electrode in anodic oxidation of dye-containing solutions

Previous work has verified the possibility to obtain mechanically, chemically and electrically stable electrodes based on manganese oxide (MnOx) thin films for anodic oxidation of solutions containing the RV5 azodye. To improve the morphological and electrochemical properties of these materials, in this study, a surface modification of the titanium support has been presented. Chemically modified surfaces were obtained by etching titanium substrates in hydrocloridric acid at high temperature. Untreated and modified electrodes were coated sequentially with a RuOx film, as interlayer and a MnOx film obtained by adopting three different techniques including anodic electrodeposition, cathodic electrodeposition and thermal decomposition. Surface morphology, topography and composition of all the electrodes were investigated by profilometric and TOF-SIMS analysis. Anodes electrochemical activities were first determined by cyclic voltammetry, and then in the treatment of solutions containing the azo dye Reactive Violet 5 (RV5), as model pollutant, in undivided cell under galvanostatic conditions. The results show that the surface microstructure modifies substantially the electrochemical response of selected electrodes.