The request for electrodes exhibiting satisfactory catalytic activity and high stability, under particular conditions of potential and current density, has stimulated the synthesis of new materials with improved performances. Among them, devices based on RuO2 and IrO2 found wide application in the field of DSAs (dimensionally stable anodes) for their ability to associate a good electrocatalytic activity to a high resistance to corrosion. Often, a greater stability leads to a decrease of catalytic activity, but it is possible to find a compromise by using mixtures of oxides. Besides the conductive and electroactive oxide (typically noble metal oxides, such as IrO2, RuO2, PtOx and RhOx), other oxides are added to the mixture (these are oxides of so-called "valve" metals, like TiO2, SnO2, Ta2O5, Nb2O5 and ZrO2), which have the dual purpose of increasing the corrosion resistance of the electrode, and to dilute the primary oxide as to minimize the device production costs. For the preparation of film electrodes, a physical vapor deposition (PVD) technique has been used: in particular, the attention was focused on the reactive sputtering. This method ensures a better homogeneity of the film, in terms of thickness and roughness, compared to conventional pyrolytic techniques used for electrodes preparation. The synthesis of thin-film-electrodes was carried out at room temperature, and their characterization was attained through electrochemical as well as surface tests; then, further information was obtained studying the catalytic properties of films towards the chlorine evolution reaction.
Preparation by physical vapor deposition and characterization of films of iridium-tin oxides
ROSESTOLATO, Davide;FERRO, Sergio;DE BATTISTI, Achille
2010
Abstract
The request for electrodes exhibiting satisfactory catalytic activity and high stability, under particular conditions of potential and current density, has stimulated the synthesis of new materials with improved performances. Among them, devices based on RuO2 and IrO2 found wide application in the field of DSAs (dimensionally stable anodes) for their ability to associate a good electrocatalytic activity to a high resistance to corrosion. Often, a greater stability leads to a decrease of catalytic activity, but it is possible to find a compromise by using mixtures of oxides. Besides the conductive and electroactive oxide (typically noble metal oxides, such as IrO2, RuO2, PtOx and RhOx), other oxides are added to the mixture (these are oxides of so-called "valve" metals, like TiO2, SnO2, Ta2O5, Nb2O5 and ZrO2), which have the dual purpose of increasing the corrosion resistance of the electrode, and to dilute the primary oxide as to minimize the device production costs. For the preparation of film electrodes, a physical vapor deposition (PVD) technique has been used: in particular, the attention was focused on the reactive sputtering. This method ensures a better homogeneity of the film, in terms of thickness and roughness, compared to conventional pyrolytic techniques used for electrodes preparation. The synthesis of thin-film-electrodes was carried out at room temperature, and their characterization was attained through electrochemical as well as surface tests; then, further information was obtained studying the catalytic properties of films towards the chlorine evolution reaction.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
