The 2025 Nobel Prize in Chemistry was awarded to Susumu Kitagawa, Richard Robson and Omar M Yaghi for developing metal-organic frameworks.
These structures, with their large cavities, enable applications like water harvesting from desert air, pollutant extraction and carbon capture.
Their work has opened new possibilities for custom-made materials with diverse functions.
The 2025 Nobel Prize in Chemistry has been awarded to three scientists for their research that paved the way for harvesting water from desert air, extracting pollutants from water, capturing carbon dioxide and storing hydrogen.
The three researchers — Susumu Kitagawa from Kyoto University, Japan, Richard Robson from the University of Melbourne, Australia and Omar M Yaghi from University of California, Berkeley, United States — were recognised “for the development of metal–organic frameworks”. Metal–organic frameworks is a new type of molecular architecture. The constructions, which have metal ions and cornerstones linked by long carbon-based molecules, have large cavities that allow molecules to flow in and out.
By varying the building blocks used in the metal–organic frameworks, chemists can design them to capture and store specific substances. These constructions can also drive chemical reactions or conduct electricity. “Metal-organic frameworks have enormous potential, bringing previously unforeseen opportunities for custom-made materials with new functions,” Heiner Linke, Chair of the Nobel Committee for Chemistry, said in a statement.
Typically, to create a new molecule, researchers combine substances that react with each other in a container. When the container is heated, the desired molecule forms — but with a range of contaminating side products.
How were metal-organic frameworks developed? The work began in 1989, when Robson combined positively charged copper ions with a four-armed molecule. When combined, the positively charged copper ions and a four-armed molecule bonded to form a well-ordered, spacious crystal with innumerable cavities.
Think of this as diamond forming a regular crystalline structure. However, unlike diamond, this new crystal construction contained a vast number of large cavities.
Robson speculated that this new form of molecular construction could help catalyse chemical reactions. However, a lot more work needed to be done. While Robson believed this molecular construction has potential, it was unstable and collapsed easily.
Then, between 1992 and 2003, Kitagawa and Yaghi addressed this issue separately. Kitagawa showed that gases can flow in and out of the constructions and predicted that metal-organic frameworks could be made flexible.
In 1997, Kitagawa and his team used cobalt, nickel or zinc ions and a molecule called 4,4′-bipyridin to create a three-dimensional metal–organic frameworks that were intersected by open channels. They then dried one of these materials, emptying it of water.
This construction was stable and the spaces could even be filled with gases. They showed that the material could absorb and release methane, nitrogen and oxygen, without changing shape. He also showed that metal organic frameworks can form soft materials.
Yaghi created a very stable metal-organic framework, giving it new and desirable properties. In 2002 and 2003, he showed that it is possible to modify metal-organic frameworks to create new properties. For instance, he produced 16 variants of a metal-organic framework with cavities that were both larger and smaller than those in the original material. One variant could store huge volumes of methane gas, which could find use in renewable natural gas-fuelled vehicles.
Since their discovery, scientists have constructed tens of thousands of metal-organic frameworks, with applications such as separating per- and polyfluoroalkyl substances or PFAS from water, breaking down traces of pharmaceuticals in the environment, capturing carbon dioxide or harvesting water from desert air and trapping ethylene gas from fruit to slow ripening process.