{"id":27595,"date":"2025-08-20T12:27:47","date_gmt":"2025-08-20T06:42:47","guid":{"rendered":"https:\/\/www.revoscience.com\/en\/?p=27595"},"modified":"2025-08-20T12:28:17","modified_gmt":"2025-08-20T06:43:17","slug":"clean-hydrogens-iridium-problem-solved-in-an-afternoon","status":"publish","type":"post","link":"https:\/\/www.revoscience.com\/en\/clean-hydrogens-iridium-problem-solved-in-an-afternoon\/","title":{"rendered":"Clean hydrogen\u2019s iridium problem? Solved in an afternoon"},"content":{"rendered":"\n
\"\"
An artistic interpretation of the new catalytic material performing a reaction to split water. Credit: Jin Huang and Siyuan Zuo<\/sup><\/em><\/figcaption><\/figure>\n\n\n\n

For decades, researchers worldwide have sought alternatives to iridium, a highly rare and expensive metal used in the production of clean hydrogen fuels.\u00a0<\/p>\n\n\n\n

Now, a powerful new tool has found one\u2014within a single afternoon.<\/p>\n\n\n\n

Invented and developed at Northwestern University, the tool is called a megalibrary. The world\u2019s first nanomaterial \u201cdata factory,\u201d each megalibrary contains millions of uniquely designed nanoparticles on one tiny chip. <\/p>\n\n\n\n

In collaboration with researchers from the Toyota Research Institute (TRI), the team used this technology to discover commercially relevant catalysts for hydrogen production. Then, they scaled up the material and demonstrated it could work within a device\u2014all in record time.<\/p>\n\n\n\n

With a megalibrary, scientists rapidly screened vast combinations of four abundant, inexpensive metals\u2014each known for its catalytic performance\u2014to find a new material with performance comparable to iridium. The team discovered a wholly new material that, in laboratory experiments, matched or in some cases even exceeded the performance of commercial iridium-based materials, but at a fraction of the cost.<\/p>\n\n\n\n

This discovery doesn\u2019t just make affordable green hydrogen a possibility; it also proves the effectiveness of the new megalibrary approach, which could completely change how researchers find new materials for any number of applications.<\/p>\n\n\n\n

The\u00a0study was published<\/a>\u00a0on August 19 in the\u00a0Journal of the American Chemical Society (JACS).<\/em><\/p>\n\n\n\n

\u201cWe\u2019ve unleashed arguably the world\u2019s 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,\u201d said Northwestern\u2019s\u00a0Chad A. Mirkin<\/a>, the study\u2019s senior author and primary inventor of the megalibrary platform. <\/p>\n\n\n\n

\u201cIn 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.\u201d<\/p>\n\n\n\n

A nanotechnology pioneer, Mirkin is the George B. Rathmann Professor of Chemistry at Northwestern\u2019s\u00a0Weinberg College of Arts and Sciences<\/a>, professor of chemical and biological engineering, biomedical engineering, and materials science and engineering at the\u00a0McCormick School of Engineering, and executive director of the\u00a0International Institute for Nanotechnology. Mirkin co-led the work with\u00a0Ted Sargent, the Lynn Hopton Davis and Greg Davis Professor of Chemistry at Weinberg, professor of electrical and computer engineering at McCormick, and executive director of the\u00a0Paula M. Trienens Institute for Sustainability and Energ<\/a>y.<\/p>\n\n\n\n

\u2018Not enough iridium in the world\u2019<\/strong><\/p>\n\n\n\n

As the world moves away from fossil fuels and toward decarbonization, affordable green hydrogen has emerged as a critical piece of the puzzle. To produce clean hydrogen energy, scientists have turned to water splitting, a process that uses electricity to split water molecules into their two constituent components\u2014hydrogen and oxygen.<\/p>\n\n\n\n

The oxygen part of this reaction, called the oxygen evolution reaction (OER), however, is difficult and inefficient. OER is most effective when scientists use iridium-based catalysts, which have significant disadvantages. Iridium is rare, expensive, and often obtained as a byproduct from platinum mining. More valuable than gold, iridium costs nearly\u00a0$5,000 per ounce<\/a>.<\/p>\n\n\n\n

\u201cThere\u2019s not enough iridium in the world to meet all of our projected needs,\u201d Sargent said. \u201cAs we think about splitting water to generate alternative forms of energy, there\u2019s not enough iridium from a purely supply standpoint.\u201d<\/p>\n\n\n\n

\u2018Full army deployed on a chip\u2019<\/strong><\/p>\n\n\n\n

Mirkin, who introduced the megalibraries<\/a> in 2016, decided with Sargent that finding new candidates to replace iridium was a perfect application for his revolutionary tool. While materials discovery is traditionally a slow and daunting task filled with trial and error, megalibraries enable scientists to pinpoint optimal compositions at breakneck speeds.<\/p>\n\n\n\n

Each megalibrary is created with arrays of hundreds of thousands of tiny, pyramid-shaped tips to print individual \u201cdots\u201d onto a surface. Each dot contains an intentionally designed mix of metal salts. When heated, the metal salts are reduced to form single nanoparticles, each with a precise composition and size.<\/p>\n\n\n\n

\u201cYou can think of each tip as a tiny person in a tiny lab,\u201d Mirkin said. \u201cInstead of having one tiny person make one structure at a time, you have millions of people. So, you basically have a full army of researchers deployed on a chip.\u201d<\/p>\n\n\n\n

And the winner is\u2026<\/strong><\/p>\n\n\n\n

In the new study, the chip contained 156 million particles, each made from different combinations of ruthenium, cobalt, manganese, and chromium. A robotic scanner then assessed how well the most promising particles could perform an OER. Based on these tests, Mirkin and his team selected the best-performing candidates to undergo further testing in the laboratory.<\/p>\n\n\n\n

Eventually, one composition stood out: <\/strong>a precise combination of all four metals (Ru52<\/sub>Co33<\/sub>Mn9<\/sub>Cr6<\/sub> oxide). Multi-metal catalysts are known to elicit synergistic effects that can make them more active than single-metal catalysts.<\/p>\n\n\n\n

\u201cOur catalyst actually has a little higher activity than iridium and excellent stability,\u201d Mirkin said. \u201cThat\u2019s rare because oftentimes ruthenium is less stable. But the other elements in the composition stabilize ruthenium.\u201d<\/p>\n\n\n\n

The ability to screen particles for their ultimate performance is a major new innovation. \u201cFor 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,\u201d said Joseph Montoya<\/a>, a senior staff research scientist at TRI and study co-author.<\/p>\n\n\n\n

In long-term tests, the new catalyst operated for more than 1,000 hours with high efficiency and excellent stability in a harsh acidic environment. It is also dramatically cheaper than iridium\u2014about one-sixteenth of the cost.<\/p>\n\n\n\n

\u201cThere\u2019s lots of work to do to make this commercially viable, but it\u2019s very exciting that we can identify promising catalysts so quickly\u2014not only at the lab scale but also for devices,\u201d Montoya said.<\/p>\n\n\n\n

Just the beginning<\/strong><\/p>\n\n\n\n

By generating massive high-quality materials datasets, the megalibrary approach also lays the groundwork for using artificial intelligence (AI) and machine learning to design the next generation of new materials. Northwestern, TRI, and Mattiq, a Northwestern spinout company, have already developed\u00a0machine learning algorithms<\/a>\u00a0to sift through the megalibraries at record speeds.<\/p>\n\n\n\n

Mirkin says this is only the beginning. With AI, the approach could scale beyond catalysts to revolutionize materials discovery for virtually any technology, such as batteries, biomedical devices, and advanced optical components.<\/p>\n\n\n\n

\u201cWe\u2019re going to look for all sorts of materials for batteries, fusion, and more,\u201d he said. \u201cThe world does not use the best materials for its needs. People found the best materials at a certain point in time, given the tools available to them. The problem is that we now have a huge infrastructure built around those materials, and we\u2019re stuck with them. We want to turn that upside down. It\u2019s time to truly find the best materials for every need\u2014without compromise.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

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