Improving the Stability of DSA Electrodes by the Addition of TiO₂ Nanoparticles

Dimensionally stable anodes (DSA) are widely used in water electrolysis, cathodic protection, wastewater treatment, metal electrowinning and chlor-alkali industry. An important parameter of these anodes is their lifetime under harsh anodic conditions. In this work, the incorporation of TiO2 nanoparticles into a thermally prepared IrO2 anode as a way of improving its service lifetime was investigated. The results show that incorporation of up to 25 wt% TiO2 nanoparticles into the coating formed crack-free structure during the thermal decomposition process and thus enhances the service lifetime of modified electrode dramatically by up to 10x compared to the pure IrO2 anode. Importantly, these nanoparticle additions have minimal effect of the anodes performance toward the oxygen evolution reaction. Further addition of TiO2 nanoparticles reduced the lifetime of the anode due to uneven distribution of the active coating over the substrate leading to electrolyte penetration to, and passivation of, the underlying titanium substrate. It is proposed that adding the right quantity of nanoparticles into the IrO2 layer improved the anodes lifetime by minimising electrolyte penetration to the substrate while increasing the mechanical strength of the layer.