Activating Oxygen Radical Coupling on Face-Shared IrO₆ Dimer Through Enhanced Electronic Coupling for Acidic Water...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The oxygen evolution reaction (OER) is crucial for energy conversion technologies.
• Achieving high activity and durability simultaneously in OER catalysts remains a significant challenge.
• Current OER mechanisms often face limitations in efficiency and stability, particularly under acidic conditions.

Purpose of the Study:

• To rationally modulate dual-metal active sites for improved OER performance.
• To investigate the mechanistic transition from adsorbate evolution mechanism (AEM) to oxide-path mechanism (OPM).
• To develop a robust OER electrocatalyst for proton exchange membrane (PEM) electrolyzers.

Main Methods:

• Synthesis of 6H-SrIrO3 via partial La substitution.
• Electronic structure analysis to understand the role of La incorporation.
• Electrochemical testing of the catalyst in a PEM electrolyzer.

Main Results:

• Partial La substitution in 6H-SrIrO3 induced a switch from AEM to OPM.
• La incorporation strengthened electronic coupling in IrO6 dimers, activating them as dual-metal centers.
• The optimized 2%La-SrIrO3 catalyst demonstrated a low overpotential and exceptional durability (>1900 h at 1 A cm-2).

Conclusions:

• The study presents a mechanistic design paradigm for robust OER electrocatalysts.
• The developed catalyst overcomes the activity-stability trade-off in acidic media.
• This work paves the way for advanced catalysts in water-splitting technologies.