Researchers at Northwestern University have developed a new material that could replace iridium in the production of clean hydrogen fuels. Iridium is rare, expensive, and essential for water splitting reactions used to generate green hydrogen, but global supply is limited and costs are high.
The team at Northwestern, collaborating with the Toyota Research Institute (TRI), used a technology called a megalibrary—a chip containing millions of uniquely designed nanoparticles—to rapidly search for alternative catalysts. This method allowed them to screen vast combinations of four abundant metals: ruthenium, cobalt, manganese, and chromium. The result was the discovery of a new catalyst that matches or even exceeds the performance of commercial iridium-based materials while costing significantly less.
“We’ve unleashed arguably the world’s most powerful synthesis tool, which allows one to search the enormous number of combinations available to chemists and materials scientists to find materials that matter,” said Chad A. Mirkin, senior author and primary inventor of the megalibrary platform at Northwestern. “In this particular project, we have channeled that capability toward a major problem facing the energy sector. That is: How do we find a material that is as good as iridium but is more plentiful, more available and a lot cheaper? This new tool enabled us to find a promising alternative and to find it rapidly.”
Ted Sargent from Northwestern added: “There’s not enough iridium in the world to meet all of our projected needs. As we think about splitting water to generate alternative forms of energy, there’s not enough iridium from a purely supply standpoint.”
The newly discovered catalyst contains precise ratios of all four metals (Ru52Co33Mn9Cr6 oxide) and has shown higher activity than iridium with excellent stability during laboratory tests. Joseph Montoya from TRI commented on its performance: “For the first time, we were not only able to rapidly screen catalysts, but we saw the best ones performing well in a scaled-up setting.”
Long-term testing demonstrated that this catalyst can operate efficiently for over 1,000 hours in harsh acidic environments while costing about one-sixteenth as much as iridium.
“There’s lots of work to do to make this commercially viable, but it’s very exciting that we can identify promising catalysts so quickly — not only at the lab scale but for devices,” Montoya said.
The use of megalibraries also enables artificial intelligence (AI) and machine learning applications in materials discovery by generating large datasets for analysis. Northwestern University researchers are already applying AI algorithms developed with TRI and Mattiq—a spinout company from Northwestern—to further accelerate discoveries.
Mirkin sees broader potential beyond hydrogen production: “We’re going to look for all sorts of materials for batteries, fusion and more... We want to turn that upside down. It’s time to truly find the best materials for every need — without compromise.”
The research was published August 19 in the Journal of the American Chemical Society (JACS). Funding came from organizations including TRI, Mattiq, BioMADE (Bioindustrial Manufacturing and Design Ecosystem), Army Research Office under award W911NF-23-1-0285, Air Force agreement FA8650-21-2-5028; standard disclaimers note these views do not necessarily represent those agencies’ official policies.