Antimony and antimony-platinum doped tin dioxide electrodes supported on titanium have been prepared by thermal decomposition. Ti/SnO 2 -Sb electrodes have a cracked-mud structure, typical of oxide electrodes prepared by thermal decomposition. The introduction of platinum in the oxide layer has a packing effect in the coating morphology. The electrochemical characterization of these electrodes has been performed in acid medium, and a relation between the roughness factor (measured from electrode capacitance) and electrochemical porosity (related to the voltammetric charge) has been established. The mechanism for the oxygen evolution reaction has been determined by Tafel measurements indicating that the electrodes prepared are nonactive electrodes. The electrocatalytic activity strongly depends on geometric factors, since the activity toward oxygen evolution increases with the electrochemical porosity. Anodic stability of Ti/SnO 2 electrodes has been checked with accelerated service life tests. The introduction of platinum in the oxide coating increases the service life by 2 orders of magnitude.

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Several antimony-and antimony-platinum-doped tin dioxide electrodes supported on titanium have been characterized by X-ray photoelectron spectroscopy (XPS) for surface analysis and secondary-ion mass spectrometry (SIMS) for in-depth profile analysis. The surface analysis of the freshly prepared electrodes indicates that the Sb/Sn ratio in the electrode surface is similar to the nominal composition in the precursor solution, but the amount of Pt is higher than this nominal composition. The presence of platinum also produces the segregation of Sb near the electrode surface. The anodic polarization treatment of the electrode produces changes in its chemical state. The growth of a passivating hydroxide in the outer layer is the main cause of the deactivation of Ti/SnO 2 -Sb electrodes. The introduction of platinum in the layer prevents the hydroxide formation and modifies the deactivation mechanism of the electrode. The growth of an isolating TiO 2 between the support and the active oxide produces the deactivation of Ti/SnO 2 -Sb-Pt electrodes.

The chlorine evolution reaction has been studied at highly boron-doped diamond thin film electrodes. The comparison of this carbonaceous material with graphite and glassy carbon points out the similar behavior in terms of diagnostic parameters and related mechanisms, without the mechanical fragility of these materials. Tafel slopes at different chloride concentrations in solution (from 0.1 to 4 M NaCl in 0.01 M HClO 4 ) and at different pHs have been determined, together with the reaction orders with respect to Cl Ϫ and H ϩ . All measurements were carried out at a constant ionic strength. The electrode characterization has been done by means of cyclic voltammetry, showing a detailed picture for the chloride oxidation and the reduction of the evolved chlorine. Significant surface modifications occur when the electrode works as an anode for oxygen evolution, while chlorine evolution does not seem to cause severe changes. As shown by tests carried out following a method suggested in the literature, the faradaic yield for chlorine production is expected to be very high. In dilute chloride media and at neutral-weakly alkaline pH, a faradaic yield of about 65% has been found; this makes use of highly doped diamond electrodes in, e.g., seawater electrolysis, quite promising.