Stable Ti/IrO<i>_x</i>−Sb₂O₅−SnO₂ Anode for O₂ Evolution with Low Ir Content

Abstract

Titanium anodes coated with a ternary iridium, antimony, and tin oxide mixture (Ti/IrOx−Sb2O5−SnO2) were investigated for oxygen evolution. In the active oxide coating, SnO2 serves as a dispersing agent, Sb2O5 as a dopant, and IrOx as a catalyst. Experimental results showed that the Ti/IrOx−Sb2O5−SnO2 electrode containing only 10 mol % of IrOx 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/IrOx under the same conditions. Instrumental analysis indicated that the IrOx−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.