Effects of the geometry and operating temperature on the stability of Ti/IrO2-SnO2-Sb2O5 electrodes for O2 evolution

Ternary IrO2-Sb2O5-SnO2 anode has shown its superiorities over IrO2 and many other electrocatalysts for O-2 evolution, in terms of electrochemical stability, activity and cost. The performance of IrO2-Sb2O5-SnO2 anodes is affected by its electrochemical properties and operating conditions. In this paper, the electrochemical stability and activity of the Ti/IrO2-Sb2O5-SnO2 anodes prepared with three different geometries were investigated under different operating conditions. It was found that anodes with large mean curvature have high electrochemical stability. Although increasing temperature results in a decrease in the stability of Ti/IrO2-Sb2O5-SnO2, the anode with a mean curvature of 200 m(-1) still shows acceptable service life even at 70 A degrees C. This tolerance of high temperature was attributed to the thermal expansion difference between the substrate and the coating layer, the redox window for Ir(V)/Ir(IV) conversion, and the redox reversibility of Sb and Sn species in the coating layer.