Photodeposited IrO2 on TiO2 support as a catalyst for oxygen evolution reaction

•IrO2/TiO2 catalyst for OER was prepared by a simple, UV light-assisted method.•The used technique leads to directly formed, highly dispersed IrO2 nanoparticles.•IrO2/TiO2 shows better intrinsic electrocatalytic activity for OER than unsupported IrO2.•Under UV light, IrO2/TiO2 shows increased stability during OER than in the dark.•The improved behavior is due to TiO2-IrO2 synergism and IrO2 activation during OER.