Optimizing the TiO2 Content to Obtain the Highest Corrosion Resistance in Ir-Ru-Ta-Based Mixed Metal Oxide Coating in Oxygen Evolution Reaction Application

In this article, the role of TiO2 on deactivation and corrosion mechanism of a MMO coating was assessed in 1 M Na2SO4 solution. The Ti/40IrO(2) + 30RuO(2) + (30 - x)Ta2O5 + (x)TiO2 anodes were prepared by thermal decomposition method. Surface morphology and microstructure of the coatings were characterized by scanning electron microscopy, energy-dispersive spectroscopy and grazing incidence x-ray diffraction analysis. The electrochemical properties and corrosion behavior of these coatings were performed by accelerated lifetime test, investigation of active surface area (q*) and electrochemical impedance spectroscopy. The results showed that the uniform dissolution of the active surface layers was the main reason behind the anode deactivation. Furthermore, addition of titanium oxide up to 15% to the above-mentioned composition improved the performance of the anode and increased its working life up to 200 h.