In a significant leap toward cost-effective green hydrogen production, researchers at Rice University have developed a new catalyst that reduces iridium usage in proton exchange membrane (PEM) electrolysers by more than 80%. The innovation directly addresses one of the most critical cost and supply challenges in the hydrogen economy.

Hydrogen is increasingly recognised as a key clean fuel in global decarbonisation efforts, capable of powering industries and transport without emissions. However, large-scale adoption has been hindered by the high price and limited availability of iridium, a rare and expensive metal—costing approximately $160 per gram—essential for withstanding the highly acidic conditions in PEM electrolysers.

“Without reducing iridium consumption, the projected demand from electrolysers alone could exceed 75% of the world’s annual supply,” explained Wang, a member of the Rice University research team. “That’s simply not sustainable if we’re serious about scaling hydrogen production.”

To overcome this barrier, the researchers designed a catalyst that embeds iridium atoms within a ruthenium oxide lattice rather than coating them on the surface. This approach reduces the amount of iridium required while maintaining high performance and long-term durability.

Working in collaboration with De Nora Tech, the team used density functional theory and Monte Carlo simulations to predict the optimal atomic configuration. “Our simulations revealed that iridium atoms in the subsurface layer play a critical role,” said Thomas Senftle, associate professor of chemical and biomolecular engineering at Rice. “They help protect the ruthenium atoms above them from dissolving under extreme electrochemical conditions.”

The resulting compound, named Ru₆IrOₓ, features a six-to-one ratio of ruthenium to iridium. The material sustained an industrial-level current density of 2 amperes per square centimetre for more than 1,500 hours with minimal degradation—demonstrating remarkable stability and performance.

“The key is achieving a uniform distribution of iridium throughout the ruthenium oxide structure,” Senftle added. “That uniformity promotes stability because iridium helps to stabilise neighbouring ruthenium atoms in the oxide lattice.”

Source: 

https://interestingengineering.com/innovation/iridium-cut-catalyst-green-hydrogen