PHYSICOCHEMICAL AND ELECTROCHEMICAL CHARACTERIZATION OF RU-BASED TERNARY OXIDES CONTAINING TI AND CE

The effect of mixing Ru and Ce has been investigated by systematically substituting Ce for Ti in 30 mol% RuO2 + 70 mol% TiO2. A set of ternary oxide electrodes with the general formula Ru0.3Ti(0.7-x)CexO2 has been prepared from x = 0 to x = 0.7 at 10 mol% intervals by thermal decomposition of aqueous acid solutions of the chlorides as precursors using Ti as a support. Ex situ characterization included TGA, XRD and SEM. Electrodes were characterized in acid solution as a function of composition by determining the open-circuit potential, the voltammetric curve and the voltammetric charge. Variables were temperature, time and atmosphere of calcination. The electrodes showed variation of the voltammetric charge and of the voltammetric features dependent on the potential window and the number of cycles. The main reason for instability appears to be the cathodic dissolution of the Ce component, which has been confirmed by analysing the solution by ICPES. Ways of minimizing this inconvenience have been explored. Preliminary results in alkali indicate excellent stability.