Thermoanalytical investigation of the formation of RuO 2-based mixed-oxide electrodes

Abstract

The processes of formation of RuO 2 TiO 2 coatings from precursor salts dissolved in isopropanol were followed by combined thermoanalytical and mass-spectrometric methods. The electrochemical characterization of the coatings was carried out by cyclic voltammetry. The pyrolysis of the titanium precursor salt, titanium diisopropoxide bis-2,4-pentanedionate, consists of four stages and involves the formation of elemental carbon in the coating. The steps of solvent desorption, oxidative cracking and combustion could be detected by comparison of the curves obtained. In the case of the pyrolysis of ruthenium and titanium salt mixtures, owing to the catalytic effect of the noble metal addition, the final decomposition temperature was reduced by more than 100 °C. In the main combustion step an almost complete conversion of the organic matter to CO 2 and H 2O takes place. The highest rate of decomposition and of heat release is observed for a coating composition between 10 and 30 mol% of Ru. Cyclic voltammetry experiments showed that the maximum charge-storage capacity, as indicated by larger surface areas, is also observed in this composition range.