Recently, the scientific world turned its gaze to Stockholm as Susumu Kitagawa, Richard Robson, and Omar Yaghi were awarded the Nobel Prize in Chemistry 2025. Their pioneering research has identified a new kind of chemical structure — metal-organic frameworks (MOFs) — that could offer solutions to the world’s biggest environmental challenges.

Another way to put it: they’ve designed molecular structures that look and function like small, intricate cages capable of trapping gases, sifting out water contaminants, removing moisture from air, and more.

The architecture of MOFs

MOFs are three-dimensional structures made of metal ions — positively charged atoms that act as strong connecting points, and organic linkers — carbon-based molecules that join these metal points together to form a network full of pores. These pores give MOFs a very large surface area, meaning they have plenty of space inside to hold other molecules. 

By combining the rigid metal ions with soft organic linkers, MOFs span an area where inorganic chemistry’s focus on metals and minerals intersects with organic chemistry, which deals with carbon-based molecules. As a result, MOFs are highly versatile and physically flexible. 

Scientists can change the type of metal ion the MOFs are made of to adjust the size and properties of their pores. This tunability lets researchers choose which molecules the MOFs adsorb, store, or release — a characteristic that contributes to applications such as carbon dioxide capture, hydrogen and methane storage, drug delivery, and water purification. Notably, they have unparalleled potential in the storage of energy and removal of contaminants.

The scientists behind the breakthrough

In the 1980s, at the University of Melbourne, Robson created the first MOFs by linking metal ions and organic molecules into extended, repeating frameworks. Inspired by the molecular crystal structure of diamonds, he aimed to create synthetic frameworks with cavities where gas molecules could be encapsulated. 

Although these early chemical frameworks were not very stable, Robson’s work laid the foundation of MOF design, showing that geometric principles could be used to guide the creation of stable, functional materials. His paper outlined how to design MOFs with specific pore sizes and connectivity, enabling applications like selective gas adsorption.

Kitagawa’s work in the 1990s at Tokyo Metropolitan University demonstrated that MOFs’ structures — with their porous design — could actually be structurally stable by using a ‘tongue-and-groove’ molecular geometry. 

Groups of protruding molecular edges, or tongues, fit into adjacent grooves similar to how we fit wood panels for flooring. Therefore, MOFs may be able to maintain their structural integrity, but also trap, or adsorb, gases into their pores and then release, or desorb, the gas. The structures remain intact as their flexibility allows them to relax and change shape to accommodate the size of guest molecules. This process is known as breathing behaviour. 

Kitagawa’s research is foundational in the use of MOFs in gas separation and storage, particularly for environmentally significant gases like methane and carbon dioxide. 

From the late ’90s to early 2000s, Yaghi researched how MOFs could selectively adsorb poisonous gases, such as ammonia, sulphur dioxide, and carbon monoxide, which could clean up the environment. Yaghi and his lab later synthesized MOFs that can harvest water from extremely dry air by adsorbing water vapour at night and evaporating it in liquid form when the structure is lightly heated during the day. This innovation could potentially clean water in desert regions. 

Kitagawa, Robson, and Yaghi’s advancements demonstrate the promise of MOFs in addressing global challenges of energy, environment, and sustainability.

Chemistry for a changing planet

The impact of MOFs reaches far beyond the lab bench, offering real-world solutions to some of the world’s most persistent challenges. From fighting climate change and pollution to improving sustainable access to clean water, these materials demonstrate that chemistry can change the world. 

As Kitagawa, Robson, and Yaghi travel to Stockholm in December to collect their medals, their research stands as a testament to the subtle, yet profound, strength of chemistry — to create solutions at the molecular scale that address the world’s biggest climate challenges.