Characterization of dsa-type oxygen evolving electrodes. Choice of base metal

In the search for a good DSA-type O2-evolving electrode, the influence of the base metal (titanium, tantalum, zirconium, niobium and some of their alloys) on the performance of IrO2-Ta2O5 coated electrodes, was investigated. The thermal behaviour and oxygen affinity sequence of the metals, in relation to the electrode preparation procedure, were determined thermogravimetrically. The chemical and electrochemical stability of the base metal was found to be directly related, through the wear mechanism, to the service life of the electrode, measured in 30% H2SO2 at 80°C and 750 mA cm−2. Tantalum-based electrodes were shown to have the highest service life; 1700 h, compared with the 120 h for titanium-based electrodes.