Nanoparticles of IrO2 or Sb-SnO2 increase the performance of iridium oxide DSA electrodes

Dimensionally stable anodes (DSAs) are widely used in electrochemical industries as gas evolution electrodes. In order to decrease the power consumption during gas evolution, the performance of the electrodes must be increased. In this study, IrO2- or Sb-doped SnO2 (ATO) nanoparticles were added to IrO2 DSAs at a level of 5-40%. The anode surfaces were characterised with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The performance of the anodes for the oxygen evolution reaction was measured in 0.5 mol L-1 H2SO4 solution potentiostatically. The performance increased for both the IrO2 and the ATO nanoparticles' addition. The maximum performance with IrO2 nanoparticles occurs when the electrode contains 40 wt% nanoparticles, with more than double the current density at 1.25 V, and for ATO, the maximum occurs at 10% nanoparticles with a 70% increase in current density. These both correspond to the maxima in electrochemically active surface area as determined by cyclic voltammetry. The improvement in performance appears therefore to be primarily caused by the increase in surface area. Addition of catalytically active nanoparticles is shown to be an effective method to increase DSA electrode performance towards the oxygen evolution reaction.