Scientists develop scalable, low-iridium electrocatalyst to accelerate green hydrogen production

A novel bulk-doped and surface-anchored heterostructure dramatically reduces expensive iridium loading while achieving high activity and long-term durability for proton exchange membrane water electrolysis.

As the global transition toward carbon neutrality accelerates, green hydrogen produced via proton exchange membrane water electrolysis (PEMWE) offers a promising pathway for clean energy storage and zero-emission industrial applications. However, widespread commercial adoption of PEMWE is severely bottlenecked by the anodic oxygen evolution reaction (OER). Current technologies rely heavily on scarce and expensive iridium (Ir) catalysts to withstand the highly acidic and corrosive operational environment.

To solve this critical bottleneck, a research team from Xi'an Jiaotong University and Nankai University has developed a facile, scalable synthetic strategy for a low-iridium heterostructured electrocatalyst (IrOx/Ir-Co₃O₄). Their study, published in ENGINEERING Energy, demonstrates a practical pathway to drastically reduce iridium usage while delivering exceptional catalytic activity and industrial-grade stability.

The catalyst is synthesized through a two-step electrochemical co-deposition process followed by programmed annealing. This strategy creates a unique heterostructure featuring bulk-doped Ir-Co₃O₄ topped with surface-anchored IrOx species. Advanced spectroscopic characterizations and density functional theory (DFT) calculations revealed that the electronic interaction between the bulk-doped matrix and surface species alters the local charge distribution, enriching electron density at the active Ir sites. This electronic tuning optimizes the binding free energies of key oxygen-containing intermediates, accelerating OER kinetics and suppressing iridium dissolution during prolonged operation.

Key Research Highlights & Findings

• Ultra-Low Iridium Usage with High Activity: The IrOx/Ir-Co₃O₄ electrocatalyst achieves a current density of 10 mA/cm² at an overpotential of just 237 mV in acidic electrolyte (0.5 M H₂SO₄)—49 mV lower than commercial IrO₂.
• Exceptional Mass Activity: With an iridium loading of only 0.13 mg/cm² (nearly an 88% reduction compared to commercial benchmarks), the catalyst delivers an outstanding mass activity of 230 A/g Ir at 1.5 V versus RHE.
• Superior Electrolyzer Performance: Integrated into a 1 cm² membrane electrode assembly (MEA) electrolyzer (Pt/C || IrOx/Ir-Co₃O₄), the cell requires only 1.773 V to achieve an industrial-level current density of 1 A/cm².
• Long-Term Durability: The MEA demonstrates stable operational durability for over 160 hours at a constant current density of 200 mA/cm².
• Industrial Scalability: Demonstrating clear potential for large-scale manufacturing, the team successfully fabricated a 100 cm² anode using the exact same protocol, achieving catalytic performance virtually identical to its 1 cm² lab-scale counterpart.

"Bridging the gap between laboratory-scale innovations and industrial implementation requires synthetic methods that are inherently simple, reproducible, and scalable," noted the authors. "This work provides an integrated design strategy for low-precious-metal catalysts that meet the rigorous performance and stability requirements of commercial green hydrogen production."

Journal: ENGINEERING Energy 

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Cite this article: Wang, Q., Liu, K., Dong, W., Chen, X., Wang, W., Fan, J., Zhang, Z., Shen, S., Wei, J., Luo, J., & Chen, J. (2026). Scalable synthesis of an IrOx/Ir-Co3O4 heterostructure for efficient and stable acidic oxygen evolution. ENGINEERING Energy, 20(5), 10869. https://doi.org/10.1007/s11708-026-1086-9