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Advanced Energy and Decarbonisation Office (AEDO)

Ultralow-Ir Single-Atom Catalysts Stabilized by Self-Coordinating Electronic Metal–Support Interaction for Long-Term Acidic Oxygen Evolution

1 October 2026

Affiliation

NUS

Focus topic

Low-carbon H2 & Derivatives

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Summary

This technology presents an iridium (Ir) single-atom catalyst supported on spinel cobalt oxide (Co₃O₄) for the acidic oxygen evolution reaction (OER) in proton exchange membrane water electrolysis (PEMWE). The catalyst operates via a self-coordinating electronic metal-support interaction (EMSI) that dynamically regulates the Ir oxidation state under operating conditions, simultaneously enhancing activity and suppressing degradation — breaking the conventional activity-stability trade-off.

Key quantitative achievements:

  1. Overpotential of 246 mV at 10 mA cm⁻² (95% iR-corrected, 0.5 M H₂SO₄)

  2. Tafel slope of 58.7 mV dec⁻¹

  3. Mass specific activity of 963.4 A g⁻¹_Ir and TOF of 0.48 s⁻¹ at 1.58 V vs RHE

  4. 94% reduction in Ir usage compared to commercial IrO₂ benchmark (0.1 vs ~1.7 mg_Ir cm⁻²)

  5. Three-electrode stability: 1000 h at 10 mA cm⁻² with decay rate of only 0.069 mV h⁻¹

  6. Integrated PEMWE stability: >1500 h at 1.0 A cm⁻² with an ultralow decay rate of 11.4 µV h⁻¹

  7. Gram-scale synthesis demonstrated; 4 cm² MEA fabricated and validated

What makes this novel compared to best-in-class technology?

Unlike conventional static EMSI approaches, this catalyst exhibits a self-coordinating, potential-dependent dynamic charge compensation at the atomic Ir–O–Co interface: the support actively back-donates electrons to Ir at high bias, suppressing overoxidation-driven dissolution while sustaining catalytic activity — simultaneously achieving both goals without trade-off, at an ultralow Ir loading.

This invention addresses the challenge of reducing iridium (Ir) usage in proton exchange membrane water electrolysis (PEMWE) for green hydrogen production. Conventional Ir-based catalysts are limited by high cost and insufficient durability at industrial current densities.

TRL Level

 1-3

Relevant for

  1. Green hydrogen producers operating large-scale PEMWE electrolysis plants

  2. PEMWE stack manufacturers and OEMs (e.g., electrolyzer system integrators)

  3. Hydrogen refuelling station operators (industrial/transport sector)

  4. Semiconductor and electronics manufacturers requiring high-purity hydrogen

  5. Catalyst and membrane electrode assembly (MEA) manufacturers supplying the PEMWE supply chain

About

NUS logo

Inventors: Chen Wei

Affiliation: National University of Singapore (NUS), Department of Chemistry

Contact NUS for licensing opportunities and more information.

Please quote ID ref [2026-032] in your email.