Exceptionally active iridium evolved from a pseudo-cubic perovskite for oxygen evolution in acid

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Water oxidation in acidic electrolytes faces challenges due to limited catalyst options and iridium's rarity.
• Iridium (Ir) is essential for its acid corrosion resistance but requires enhanced intrinsic activity for large-scale use.

Purpose of the Study:

• To design and investigate a novel perovskite catalyst for robust water oxidation in acidic media.
• To enhance the intrinsic activity of iridium for improved water electrolysis.

Main Methods:

• Synthesis of a pseudo-cubic SrCo0.9Ir0.1O3-δ perovskite catalyst.
• Electrochemical characterization to evaluate catalytic performance and stability.
• Analysis of surface reconstruction and its impact on catalytic activity.

Main Results:

• The designed SrCo0.9Ir0.1O3-δ catalyst exhibits exceptionally high intrinsic activity, with turnover frequencies over two orders of magnitude greater than IrO2.
• Surface reconstruction involving Sr and Co leaching was observed during electrochemical cycling.
• The reconstructed surface, rich in corner-shared, under-coordinated IrOx octahedrons, is identified as the source of high activity.

Conclusions:

• A novel perovskite catalyst demonstrates significantly enhanced iridium activity for water oxidation.
• Surface reconstruction plays a critical role in achieving superior catalytic performance.
• This work offers a promising pathway for developing cost-effective and highly active iridium-based electrocatalysts.