Stable Ti/IrOx−Sb₂O₅−SnO₂ Anode for O₂ Evolution with Low Ir Content

Titanium anodes coated with a ternary iridium, antimony, and tin oxide mixture (Ti/IrO x −Sb 2 O 5 −SnO 2 ) were investigated for oxygen evolution. In the active oxide coating, SnO 2 serves as a dispersing agent, Sb 2 O 5 as a dopant, and IrO x as a catalyst. Experimental results showed that the Ti/IrO x −Sb 2 O 5 −SnO 2 electrode containing only 10 mol % of IrO x nominally in the coating had a service life of 1600 h in 3 M H 2 SO 4 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 −Sb 2 O 5 −SnO 2 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 TiO 2 interlayer formed during calcination.