Application and Advantages of Iridium Catalysts in Chemical Reactions
Abstract
Based on data from leading international academic journals and industry research reports as of April 2026, this report systematically reviews the specific mechanisms of action and performance advantages of iridium catalysts in key chemical reactions including the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), hydrogen oxidation reaction (HOR), propane dehydrogenation, asymmetric hydrogenation, and ammonia oxidation. Analysis indicates that iridium possesses irreplaceable strategic value in extreme catalytic environments such as acidic oxygen evolution, owing to its extremely high thermal stability (melting point 2446°C), excellent corrosion resistance (non-oxidation below 2000°C), and unique electronic structure. Concurrently, low-iridium technologies and the improvement of recycling systems are emerging as critical directions for industrial development.
I. Application of Iridium Catalysts in Water Electrolysis for Hydrogen Production
1.1 Oxygen Evolution Reaction (OER)
At the anode of proton exchange membrane water electrolyzers (PEMWE), iridium-based catalysts represent the only commercially applied acidic OER catalyst system. Key advances in 2026 include:
| Catalyst System | Key Performance Parameters | Research Institution | Journal |
|---|---|---|---|
| IrOₓ/TaC | 1.71V @ 1.0 A cm⁻², mass activity 487 A gIr⁻¹, degradation rate 36 μV h⁻¹ | Brookhaven National Laboratory | ACS Catal. (2026) |
| IrNdMnOx | 2.3 times higher area-specific activity than commercial IrO₂, 50% reduction in iridium dissolution | Li Can Academician Team | Angew. Chem. (2026) |
| Ir₃Te₈ | 248.5 mV @ 10 mA cm⁻², stable operation for 1000 hours | Harbin Institute of Technology | Chem Catalysis (2026) |
1.2 Hydrogen Evolution Reaction (HER) and Hydrogen Oxidation Reaction (HOR)
- High-Entropy Iridium Alloys: C15-(IrRh)₂PrNdTb alloy enhances alkaline HER efficiency through atomic hydrogen spillover effects.
- Coordination-Engineered Iridium Clusters: Nitrogen-doped carbon-supported iridium cluster catalysts exhibit HOR activity comparable to commercial Pt/C, achieving high power density output in fuel cells.
II. Application of Iridium Catalysts in Organic Synthesis and Petrochemical Catalysis
2.1 Propane Dehydrogenation
The research team led by Professor Liu Guozhu from Tianjin University has developed an IrGe@S-1 iridium single-atom catalyst, achieving ultra-long-term stable operation exceeding 800 hours with extremely high activity and coking resistance. The optimized catalyst exhibited an unprecedented propylene formation rate of 1249.2 molC₃H₆ gIr⁻¹ h⁻¹ at 600°C. The catalyst demonstrated excellent stability under pure propane feed conditions at 580°C and a high weight hourly space velocity of 20 h⁻¹, indicating that one tonne of catalyst has the potential to produce 9,000 tonnes of propylene without regeneration. This research was published as a cover article in JACS (2026).
2.2 Asymmetric Hydrogenation and C–H Bond Activation
Chiral spirocyclic iridium catalysts have demonstrated exceptional performance in the asymmetric hydrogenation of carbonyl compounds. Iridium-catalyzed C–H bond activation is employed for constructing C–N bonds.
2.3 Ammonia Oxidation and Direct Ammonia Fuel Cells
- PtIr Nanowires: Mass activity of 124 mA mg⁻¹, 2.2 times that of Pt/C.
- PtIr-Zn Nanocubes: Onset potential of 0.355 V, peak power density of 76.0 mW cm⁻².
III. Core Advantages of Iridium Catalysts
| Advantage Dimension | Technical Characteristics |
|---|---|
| Thermal Stability | Melting point 2446°C; no oxidation in air below 2000°C |
| Chemical Stability | Insoluble in acids and aqua regia; resistant to strong acid/strong oxidizing environments |
| Tunable Electronic Structure | 5d⁷6s² electronic configuration; flexible coordination environment design |
| Maximum Atom Utilization | Single-atom catalysts achieve 100% theoretical atom efficiency |
| Multifunctional Applicability | Excellent performance in acidic/alkaline/organic phases |
IV. Market Landscape and Strategic Value
- Supply Landscape: Global annual production of 7–9 tonnes; South Africa controls over 83% of supply.
- Demand Structure: Catalysts account for 72%, electronics 9%, chemical manufacturing 11%.
- Price Trend: As of March 2026, iridium price at 2,140 RMB/g, accumulating a 71% increase year-to-date.
- Market Size: Global iridium market at US$1.46 billion in 2026, projected to reach US$2.28 billion by 2035 (CAGR 4.9%).
V. Technology Development Trends
- Low-Iridium Technologies: Kyoto University has reduced usage by over 90%; VSParticle technology achieves 90% reduction; KIST technology reduces loading to 1.5%.
- Recycling: Current recycling rate approximately 24%, with a target of 90%.
VI. Conclusion
By virtue of its unique thermal stability, chemical inertness, and electronic structure, iridium catalysts occupy an irreplaceable strategic position in extreme catalytic environments such as acidic oxygen evolution. With breakthroughs in low-iridium technologies and the improvement of recycling systems, iridium catalysts are expected to support the global energy transition and chemical industry upgrade on a broader scale.
