Abstract
Titanium electrodes coated with mixtures of IrO2 and Ta2O5 were prepared using different compositions of precursor solutions and at different thermal decomposition temperatures. The mixed effects of Ir mole ratio and thermal decomposition temperature on the crystallographic structure, especially amorphization of the IrO2-Ta2O5 coatings, were investigated, and those effects on the suppression of anodic oxidation of Pb(II) to PbO2 as a typical example of an unwanted side reaction and on the electrocatalysis for oxygen evolution were also studied. The mixed oxide coatings became amorphous when the Ir ratio and/or thermal decomposition temperature decreased. The amorphization of the coatings was effective to suppress anodic PbO2 deposition because of the increase in nucleation overpotential of PbO2 on the amorphous coatings.
