A new open-access paper in Energy & Environmental Materials describes an ultra-low iridium PEM anode that uses about a tenth of the usual iridium and still outperforms a conventional reference. We synthesised the catalyst and co-authored the study with the German Aerospace Center (DLR), Forschungszentrum Jülich, the Institute of Catalysis and Petrochemistry (CSIC, Madrid), the ALBA Synchrotron and the University of Stuttgart.
The headline numbers
The anode catalyst layer held 0.2 mg Ir/cm². Counting all iridium at the anode interface, the paper puts the effective loading at about 0.25 mg Ir/cm². Tested at 80 °C and ambient pressure on a standard PEM membrane:
- 2.82 A/cm² at 2.0 V at the start of the test, about 63 % efficiency (LHV).
- Reproducible: three independently assembled cells gave 2.75–2.87 A/cm² at 2.0 V (2.815 ± 0.05 A/cm²).
- Better than ten times the iridium: a reference cell with a commercial catalyst at 2 mg Ir/cm² reached 2.74 A/cm² at 2.0 V under identical conditions.
- 500 hours at a constant 2 V, with a gradual, small loss of current density, below 1 % in each measured interval.
For a PEM operator, 2.8 A/cm² at 2 V means more hydrogen per square metre of membrane. Doing it with a tenth of the iridium tackles the material that most limits PEM scale-up.
Why it matters
Plenty of low-loading catalysts look good at the start of a test. What makes this study useful is the full package: a repeated, benchmarked result at high current density. That is the evidence engineers need before specifying reduced-iridium CCMs, and it shows where the next gains must come from: stabilising the catalyst-layer structure and the ionomer, not only making more active catalysts.
We supply ultra-low iridium PEM anode catalysts and CCMs. Our OXYGN-M article covers our product results at 0.2 mg Ir/cm² (1.86 V at 2 A/cm², more than 1,000 hours without degradation), and the OXYGN PEM product page lists formats and samples.
Read the paper: S. S. Ambu, N. Utsch, T. Morawietz, M. Retuerto, S. Rojas, O. Usoltsev, M. Goll, D. García Sanchez, A. Glüsen, A. S. Gago, S. S. Hosseiny, K. A. Friedrich, Energy & Environmental Materials 9(4) (2026) e70242, open access. doi.org/10.1002/eem2.70242