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

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Iridium-based perovskite oxides are effective electrocatalysts for the oxygen evolution reaction (OER).
• Reducing iridium consumption in these catalysts is crucial for cost-effectiveness.

Purpose of the Study:

• To investigate the impact of iron (Fe) doping on the OER activity of monoclinic strontium iridate (SrIrO3).
• To explore strategies for enhancing electrocatalyst performance while minimizing precious metal usage.

Main Methods:

• Systematic doping of Fe into monoclinic SrIrO3.
• Structural characterization to observe phase changes with increasing Fe/Ir ratios.
• Electrochemical testing in 0.1 M HClO4 solution to evaluate OER activity.

Main Results:

• Monoclinic SrIrO3 structure was maintained for Fe/Ir ratios < 0.1/0.9; higher ratios induced a phase transition.
• SrFe0.1Ir0.9O3 exhibited the highest OER activity, with an overpotential of 238 mV at 10 mA cm-2.
• Improved performance was linked to Fe-induced oxygen vacancies and the formation of IrOx species.

Conclusions:

• Fe doping effectively enhances the OER activity of SrIrO3.
• Oxygen vacancies and specific active sites play a key role in the improved catalytic performance.
• This study provides a reference for tuning perovskite electrocatalysts using Fe doping for various applications.