The effect of ruthenium content on the service lifetime of Ti/RuO2-Sb2O5-SnO2 DSA for oxygen evolution

This work explores the opportunity to reduce the cost and increase the stability of RuO2-based electrocatalyst for oxygen evolution reaction by coating ternary oxide RuO2-Sb2O5-SnO2 on chemically stable titanium support. An active and stable type of Ti/RuO2-Sb2O5-SnO2 dimensionally stable anodes (DSA) was studied with different mole ratios of ruthenium prepared by using thermal deposition method. The metal oxides coating layer was maintained around 15 g m-2. In this ternary oxide coating, RuO2 serves as the catalyst, SnO2 as the dispersing agent, and Sb2O5 as the dopant. The morphology by SEM showed that the compact and uniform surface morphology that indicates a favorable dispersion of species of 10%, 20% and 30% ruthenium samples. Further increase of ruthenium content, surface structure with more agglomerated particles of RuO2 and the coating surface becomes less compact. The microstructure by XRD indicates that 10%, 20% and 30% ruthenium samples well intermix with Sb2O5, when ruthenium content exceeded 50% in the active coating layer, new and noticeable peaks corresponding to ruthenium oxide appear. Effects of ruthenium content on Ti/RuO2-Sb2O5-SnO2 anodes in terms of both catalyst activity and the catalyst corrosion for oxygen evolution reaction were investigated. The electrochemical characterization of these electrodes has been performed in acid medium, and the reversibility, electrochemical porosity (related to voltammetric charge), kinetic parameters (related to Tafel measurements) and electrochemical resistance (related to electrochemical impedance spectroscopy) have been established. The best activity performances were achieved by 75% nominal ruthenium content. The value of qaqc-1 was approximately