Three scientists who pioneered a new class of molecular materials resembling microscopic sponges were awarded the 2025 Nobel Prize in Chemistry on Wednesday. Susumu Kitagawa of Kyoto University in Japan, Richard Robson of the University of Melbourne in Australia, and Omar M. Yaghi of the University of California, Berkeley, will share the prize for their foundational work in designing and synthesizing metal-organic frameworks, or MOFs.
These crystalline structures, composed of metal ions linked by organic molecules, are renowned for their vast internal surface areas and tunable pores. This unique architecture allows them to capture, store, and release a wide variety of molecules with high precision. The Royal Swedish Academy of Sciences recognized the laureates for creating a revolutionary type of molecular architecture with far-reaching applications, from harvesting water in the desert and capturing carbon dioxide to delivering targeted pharmaceuticals.
A New Frontier in Chemistry
The laureates’ work, conducted separately but building on each other’s breakthroughs, established a new branch of chemistry known as reticular chemistry. This field involves stitching molecular building blocks together into predetermined, grid-like structures. MOFs are a primary example of this principle, where metal atoms or clusters serve as the nodes, or joints, and organic molecules act as the linkers, or struts, that connect them into a repeating, scaffold-like pattern.
The result is a material that is mostly empty space. The pores within these frameworks can be tailored with great precision by changing the size and chemical properties of the metal and organic components. Unlike other porous materials like zeolites, which have rigid structures, many MOFs are flexible and can respond to external stimuli. In a key 1998 paper, Susumu Kitagawa described this vision, highlighting how the flexibility and chemical diversity of MOFs would allow for the integration of many different functions. This designability has led to the creation of more than 90,000 different MOFs to date.
From Theory to Functional Materials
The Pioneering Laureates
The development of MOFs progressed over several decades through the distinct contributions of the three laureates. Richard Robson, a lecturer and researcher at the University of Melbourne since 1966, produced the first metal-organic frameworks in the early 1990s. His work demonstrated how to create stable, extended structures by design.
Omar M. Yaghi, a Jordanian-American chemist, is credited with advancing the field significantly and coining the term reticular chemistry. A major breakthrough came in 1999 with his development of MOF-5, a highly stable and porous framework built from zinc oxide clusters that demonstrated unprecedented surface area and gas storage potential. This work proved that MOFs could be robust and highly functional, setting the stage for their widespread application. Yaghi said his lifelong love of chemistry began at age 10 when he discovered a book on molecules in a library.
Working in Japan, Susumu Kitagawa contributed critical insights into the dynamic properties of MOFs. He explored how their flexible structures could change shape to selectively admit or block certain molecules, a property crucial for gas separation and sensing applications.
Applications Spanning Global Challenges
The practical uses for metal-organic frameworks are remarkably diverse, addressing some of the world’s most pressing environmental, energy, and health problems. Their exceptional capacity for gas storage and separation makes them prime candidates for carbon capture technologies, where they can selectively trap carbon dioxide from industrial emissions. One such material, CALF-20, is already being tested in a factory setting for this purpose. MOFs are also being developed to safely store hydrogen and methane for clean energy applications.
Environmental and Industrial Uses
One of the most celebrated applications is the ability to harvest water from the air, even in arid desert climates. Certain MOFs can absorb water molecules at night when humidity is higher and release clean water when warmed by the sun. In another environmental application, researchers are using MOFs to extract PFAS and other pollutants from water sources. Their tunable pores can be designed to capture specific toxic gases or to trap ethylene, a gas that causes fruit to ripen, thereby extending the shelf life of produce.
Biomedical and Catalytic Frontiers
In the medical field, the porous nature of MOFs makes them ideal carriers for drug delivery. They can encapsulate therapeutic agents and release them in a controlled manner at specific sites within the body. Their high surface area and modifiable chemistry also make them effective in biosensing, where they can detect specific biomolecules. Furthermore, MOFs show great promise as catalysts, acting as microscopic reaction chambers that can speed up chemical reactions with high selectivity, sometimes outperforming traditional catalysts like zeolites.
A Foundation for Future Innovation
The award to Kitagawa, Robson, and Yaghi recognizes decades of fundamental “blue-sky” research that has unlocked a powerful new platform for materials science. The ability to construct materials from the molecule up provides chemists with a powerful toolkit for solving critical challenges. Researchers believe the potential of these materials is so vast that they may become as important in the 21st century as plastics were in the 20th. The Nobel committee noted that by creating entirely new rooms for chemistry, the laureates have brought the greatest benefit to humankind, in the spirit of Alfred Nobel’s will.
