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

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