SURFACE CHEMICAL-CHANGES OF MIXED-OXIDE FILMS IN CL2 ANODIC PRODUCTION

The recent development of specific and sensitive surface techniques has prompted new studies of electrode properties, in particular of their catalytic activity. Many papers have reported the use of X-ray photoelectron spectrometry, Rutherford backscattering spectrometry, secondary ion mass spectrometry etc. in the analysis of mixed-oxide films, and interesting results concerning electrochromic and catalytic properties have been shown. The influence of the method of preparation has also been confirmed, together with the important role of microstructural composition. In previous studies, our group performed composition analyses and depth profiles of RuO2/TiO2 and IrO2/TiO2 Mixed-oxide coatings by secondary ion mass spectrometry (SIMS). Many positive- and negative-ion species are of particular interest in characterizing electrodes synthesized by different methods. This paper presents the results obtained by SIMS analysis of IrO2/RuO2/TiO2 films before and after their use in Cl2 anodic production. Mass spectra obtained under different experimental conditions are reported and the aspects related to surface compositon modifications induced by Cl2 evolution on electrode films are discussed.