Ruthenium-Iridium compound with catalytic effects

[Astronuc]

Engineers slash iridium use in electrolyzer catalyst by 80%, boosting path to affordable green hydrogen
https://news.rice.edu/news/2025/eng...er-catalyst-80-boosting-path-affordable-green

In the global race to decarbonize, hydrogen stands out as one of the most promising clean fuels. But despite its potential to power industries and transportation without emitting carbon, producing hydrogen sustainably in a water electrolyzer has been limited by the high cost and scarcity of one critical ingredient: iridium.

Now, a team of researchers at Rice University has developed a new catalyst that dramatically reduces the amount of iridium needed in proton exchange membrane (PEM) water electrolyzers, a key technology for generating green hydrogen from water. Their innovation — an iridium-stabilized ruthenium oxide catalyst that uses just one-sixth as much iridium as conventional systems — maintains industrial-level performance for more than 1,500 hours of continuous operation. The research was recently published in Nature Nanotechnology.

“This is a significant step toward making green hydrogen more accessible and scalable,” said Haotian Wang, associate professor of chemical and biomolecular engineering at Rice. “By reducing iridium use by over 80%, we’re addressing one of the biggest economic and supply chain bottlenecks in the hydrogen economy.”

Current PEM electrolyzers rely heavily on iridium because it is one of the few metals that can withstand the harsh, acidic conditions needed to split water efficiently. But iridium is among the rarest elements on Earth — its price is currently around $160 per gram — and global production is extremely limited.

Ruthenium is also fairly expensive (a year ago it was about $490/ troy oz, but has nearly doubled in price over the past year, now about $910/ troy oz). I tracks prices of Pt, Pd, Ru, Ir and Ru. Of the 5 metals, rhodium (Rh) is the most expensive. A year ago, Rh and Ir were close in price, but now Rh is about $7325/ troy oz, while Ir is $4575 / troy oz, which is less than it was a year ago.
https://matthey.com/products-and-markets/pgms-and-circularity/pgm-management

the Rice team, working with industrial collaborators at De Nora Tech, combined density functional theory and Monte Carlo simulations to design a new atomic structure where iridium atoms are strategically embedded within a ruthenium oxide (RuO2) lattice. This arrangement provides stability from beneath the surface, an unexpected discovery that allowed the researchers to achieve durable performance with far less iridium.

Experimentally, the team synthesized a catalyst dubbed Ru₆IrOₓ, representing a ruthenium-to-iridium atomic ratio of 6-to-1. The material demonstrated exceptional long-term stability, sustaining 2 amperes per square centimeter of current density (an industrial benchmark) for over 1,500 hours with minimal degradation.

Low-iridium stabilized ruthenium oxide anode catalyst for durable proton-exchange membrane water electrolysis
https://www.nature.com/articles/s41565-025-02030-y