IrO2 nanoparticles supported on submicrometer-sized TiO2 as an efficient and stable coating for oxygen evolution reaction

The sluggish kinetics of the oxygen evolution reaction (OER) refers to the major contributor to the energy losses in electrowinning of metals. Improving the stability in the long term and activity of the electrocatalyst for OER take on a critical significance in reducing the energy consumption. An efficient and stable OER electrode (named as Ti/SMST/IrO 2 electrode) was prepared in this study by supporting IrO 2 nanoparticles on the surface of the submicrometer-sized TiO 2 (SMST) interlayer. The obtained results indicated that the IrO 2 nanoparticles approximately 14 nm in size were supported onto the submicrometer-sized TiO 2 particles’ surface and exhibited a cactus-like morphology. The Ti/SMST/IrO 2 electrode with the SMST interlayer prepared at 450 °C exhibited the highest electrocatalytic activity in terms of OER for its largest active surface area. This electrode showed an overpotential of 350 mV at a current density of 50 mA cm −2 and displayed a remarkable electrochemical stability of 443 h at a high current density of 2 A cm −2 in H 2 SO 4 solution without significant change in OER activity. The prepared Ti/SMST/IrO 2 electrode with high electrocatalytic performance is considered one of the promising electrodes for OER.