Iron-Doped Monoclinic Strontium Iridate as a Highly Efficient Oxygen Evolution Electrocatalyst in Acidic Media

Ir-based perovskite oxides are efficient electrocatalysts for anodic oxygen evolution. This work presents a systematic study of the doping effects of Fe on the OER activity of monoclinic SrIrO₃ to reduce the consumption of Ir. The monoclinic structure of SrIrO₃ was retained when the Fe/Ir ratio was less than 0.1/0.9. Upon further increases in the Fe/Ir ratio, the structure of SrIrO₃ changed from a 6H to 3C phase. The SrFe_0.1Ir_0.9O₃ had the highest activity among the investigated catalysts with the lowest overpotential of 238 mV at 10 mA cm^-2 in 0.1 M HClO₄ solution, which could be attributed to the oxygen vacancies induced by the Fe dopant and the IrOx formed upon the dissolution of Sr and Fe. The formation of oxygen vacancies and uncoordinated sites at the molecular level may be responsible for the improved performance. This work explored the effect of Fe dopants in boosting the OER activity of SrIrO₃, thus providing a detailed reference to tune perovskite-based electrocatalyst by Fe for other applications.