Switching the Reaction Pathway to the Oxide Path for High-Efficiency Acidic Oxygen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Dynamic structure-activity relationships in oxygen evolution reaction (OER) are difficult to study due to catalyst complexity.
• Ca2IrO4, with its unique 1D IrO6 octahedra chains, serves as a model catalyst.

Purpose of the Study:

• To decode the mechanistic evolution of Ca2IrO4 during OER.
• To investigate the synergistic interplay between different facets of the catalyst.
• To establish adaptive coordination reconstruction as a strategy for designing efficient OER catalysts.

Main Methods:

• Employing Ca2IrO4 as a model catalyst.
• Utilizing in situ characterization techniques.
• Performing theoretical calculations.
• Testing catalyst performance in proton exchange membrane water electrolysis (PEMWE).

Main Results:

• Ca2IrO4 (L-H-CIO) achieves exceptional OER performance with a low overpotential (279 mV at 10 mA cm-2) and 200-h stability.
• The catalyst demonstrates high activity (1.78 V @ 2.0 A cm-2) and stability (>500 h at 1.0 A cm-2) in PEMWE.
• Adaptive surface reconstruction drives a mechanistic transition from adsorbate evolution mechanism (AEM) to oxide path mechanism (OPM).

Conclusions:

• Adaptive surface reconstruction is a key factor in enhancing OER catalyst performance.
• The reconstructed (001) surface with edge-sharing IrO6 octahedra facilitates the OPM.
• This work provides a roadmap for designing next-generation OER catalysts through adaptive coordination reconstruction.