Atomic Insights into the Competitive Edge of Nanosheets Splitting Water

Lorenz J Falling ^1,2, Woosun Jang ^1,3, Sourav Laha ^4,5

¹Fritz Haber Institute of the Max Planck Society, Berlin 14195, Germany.
²School of Natural Sciences, Technical University, Munich 85748, Germany.
³Integrated Science & Engineering Division, Underwood International College, Yonsei University, Incheon 21983, Republic of Korea.
⁴Department of Chemistry, National Institute of Technology Durgapur, Durgapur 713209, West Bengal, India.
⁵Max Planck Institute for Solid State Research, Stuttgart 70569, Germany.
⁶Leiden Institute of Chemistry, Leiden University, 2300 Leiden, RA, Netherlands.
⁷Experiments Division, ALBA Synchrotron Light Source, Cerdanyola del Vallés, Barcelona 08290, Spain.
⁸Department of Physics, Tamkang University, New Taipei City 251301, Taiwan.
⁹Wallenberg Initiative Materials Science for Sustainability, Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg 41296, Sweden.
¹⁰Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.

⁰Fritz Haber Institute of the Max Planck Society, Berlin 14195, Germany.

Journal of the American Chemical Society +

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September 25, 2024

View abstract on PubMed

Summary

Iridium oxohydroxides (IOHs) are key catalysts for the oxygen evolution reaction (OER). This study reveals atomic-level design rules for IOHs, balancing activity and stability for efficient electrocatalysis.

Area Of Science

Electrocatalysis
Materials Science
Surface Chemistry

Background

The oxygen evolution reaction (OER) is crucial for power-to-X applications like green hydrogen production.
Iridium oxohydroxides (IOHs) offer a balance of activity and stability in acidic electrolytes for OER.
Understanding the atomic structure-activity-stability relationship in IOHs is vital for catalyst design.

Purpose Of The Study

To establish simple, atomistic design rules for iridium oxohydroxides (IOHs) to predict their stability and reactivity in the oxygen evolution reaction (OER).
To investigate crystalline IrOOH nanosheets as a lead material for OER catalysis, offering high catalyst utilization and predictable structure.

Main Methods

Literature review and experimental studies on various IOHs, focusing on crystalline IrOOH nanosheets.
Analysis of the atomic structure, including the role of pyramidal trivalent oxygens (μ3Δ-O) and coordinative unsaturated edge sites (μ1-O oxyls).
Comparison with existing IOHs and literature data to generalize findings.

Main Results

Crystalline IrOOH nanosheets exhibit excellent stability and surpass the activity of amorphous IOHs.
A dense bonding network of μ3Δ-O confers structural integrity, while reversible reduction to an electronically gapped state enhances stability under reductive potentials.
Reactivity is attributed to μ1-O oxyls at edge sites, possessing radical character.

Conclusions

Developed generalized design rules for predicting IOH stability and reactivity from atomistic models.
The findings provide a foundation for rational atomic design strategies for next-generation OER catalysts.
Highlights the potential of crystalline IrOOH nanosheets for efficient and stable electrocatalysis.

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