No abstract

Titanium anodes coated with a ternary iridium, antimony, and tin oxide mixture (Ti/IrO x −Sb2O5−SnO2) were investigated for oxygen evolution. In the active oxide coating, SnO2 serves as a dispersing agent, Sb2O5 as a dopant, and IrO x as a catalyst. Experimental results showed that the Ti/IrO x −Sb2O5−SnO2 electrode containing only 10 mol % of IrO x nominally in the coating had a service life of 1600 h in 3 M H2SO4 solution under a current density of 1 A cm-2 at 35 °C, compared with 355 h for Ti/IrO x under the same conditions. Instrumental analysis indicated that the IrO x −Sb2O5−SnO2 was a metastable solid solution with a compact structure, which contributes to the superstable nature of the electrode together with the good conductivity and the improvement of bonding with the TiO2 interlayer formed during calcination.

Anodic oxidation is a promising process for degrading toxic and biologically refractory organic pollutants present in wastewater treatment. Proper selection of electrodes is the key to reach effective and economic operation. In this study, two types of electrodes, i.e. the recently developed Ti/BDD and Ti/SnO 2 -Sb 2 O 5 , which is generally believed to be superior to the conventional electrodes, were compared under the same conditions. It was found that the Ti/ BDD electrode could mineralize both phenol and reactive dyes effectively. But the Ti/SnO 2 -Sb 2 O 5 electrode could only mineralize phenol. When oxidizing more refractory reactive dyes, it demonstrated very poor activity. In addition, the Ti/BDD electrode had a service life of 264 h in an accelerated life test, but the Ti/SnO 2 -Sb 2 O 5 was irreversibly damaged within several seconds. The direct experimental comparison in the present study indicates that the Ti/BDD electrode is much better than the Ti/SnO 2 -Sb 2 O 5 electrode for pollutant oxidation.