Nobel prizewinner Omar Yaghi says his invention will change the world

Civilizations name their ages after materials. In school we learn about the Stone Age, the Bronze Age – and we are currently in a silicon age characterized by computers and telephones. What could define the next age? Omar Yaghi of the University of California, Berkeley, thinks a family of materials he helped develop in the 1990s has a good chance. These are metal-organic structures (MOFs), and figuring out how to make them earned him a share of the 2025 Nobel Prize in Chemistry.

MOFs, and their cousins ​​covalent organic structures (COFs), are crystalline materials, but what sets them apart is their incredible porosity. In 1999, Yaghi and his colleagues made a splash by synthesizing a zinc-based material called MOF-5 that was so riddled with pores that a few grams of it had an internal surface area comparable to that of a football field (see diagram below). The inside of the material was indeed much larger than its outside.

For decades, Yaghi has been at the forefront of creating new MOFs and COFs, a discipline known as reticular chemistry, and determining their utility. Because other molecules can be sucked into the abundant pores of these materials, they prove excellent at harvesting water from arid desert air, absorbing carbon dioxide from the atmosphere, and much more. Yaghi spoke to New scientist why he’s optimistic about this work, the past, present and future of reticular chemistry – and why he thinks the era of these materials is beginning to dawn.

Karmela Padavic-Callaghan: What initially attracted you to reticular chemistry?

Omar Yaghi: When we started working with MOFs, we didn’t think we were tackling societal challenges – it was an intellectual challenge. We wanted to find a way to make materials one molecule at a time, like building a building or programming molecules like Lego. But it was a really awesome chemistry challenge. For many people, it was an article of faith that it wouldn’t work, that pursuing this approach was a waste of time.

Why did designing materials this way seem so impossible?

The main challenge with building materials in a rational way is that usually when you mix the chemical elements, you end up putting them together in a messy and difficult to characterize way. This is not surprising given the laws of physics which tell us that nature tends toward high entropy or disorder. Instead, we wanted to end up with crystals, ordered matter with a periodic, repeating structure.

It’s a bit like asking a children’s room to make a perfect circle: it takes a lot of work, and when they do it, they can always disassociate or “unstick” their hand and take too long to complete the circle again. In other words, we were trying to do what nature does when it crystallizes diamonds over the course of billions of years – but in one day. But I knew deep down that everything can crystallize if you know how.

In 1999, your instincts were right and your team reported the synthesis of MOF-5which was unprecedentedly stable. Did you foresee that a material like this could eventually become useful?

We identified a solvent that could help synthesize stable MOFs and were then able to understand how it worked. We realized that the presence of its molecules in the mixture was absolutely crucial to modulate the tendency to disorder. Since then, thousands of researchers have used this method.

At first I was just excited about making beautiful crystals. Then we saw their stunning properties and were able to say, “Wow, what can we do with this?” And once we know the porosity of these materials, we immediately think about trapping the gases. These materials encompass compartments of space where a molecule of water, carbon dioxide, or something else might be found.

Tell me about your thoughts on making these materials these days.

When I cook, I don’t like having to do more than three steps and I don’t use butter. So the challenge is how to get a main dish in so few steps and using only healthy ingredients. This philosophy carried over to my chemistry as well. In other words, I want to keep the process simple and only use the chemicals we actually need.

The first step is to choose the structure of the material. The second is to decide on the size of your pores. You can also do chemistry on the backbone and add molecules to it to help capture other compounds in the pores. The third step is to let the carbon dioxide or whatever material you built the material for be vacuumed up. That’s how simple and complex the process is.

What kind of new technologies has this process allowed you to exploit?

Once you learn how to design materials at the molecular level, that’s the ultimate achievement, a geological change. My vision, and that of the company I founded in 2020, Atoco, is to move from molecule to society, to look at where there is no material for a job or where it is doing it wrong, and then rationally design a better one. As we improve our ability to manufacture materials, we will improve societal standards.

In 2024, we reported the best material yet for capturing carbon dioxide, called COF-999. It captures it from the air and we’ve tested it for over 100 capture cycles. [expelling] carbon dioxide here in Berkeley. Atoco aims to use reticular materials such as COF-999 to build carbon capture modules that could work in industrial settings, but also in residential buildings.

We have also developed materials capable of capturing thousands of liters of water per day from the atmosphere. This is the basis of our devices that can extract water vapor from the air even in places where humidity is below 20%, such as the desert areas of Nevada. I think in 10 years water harvesting will be mainstream technology.

There are other technologies capable of capturing water, such as devices that condense atmospheric vapors, as well as other devices capable of capturing CO2. How do MOFs and COFs compare?

We have so much control over the chemistry that we can make our devices sustainably. They could work for many, many years, and at the end of the journey of the MOF part of the device, you can disassemble it in the water in such a way that no MOF escapes into the environment. So, in a world where MOFs are sized at several tons and used in many different applications, we will not face a “MOF waste problem”.

And these devices can be much more energy efficient because, for example, we’ve figured out how to use ambient sunlight to make water butts release water. For carbon capture devices, we could also use waste heat from industrial processes [to get them to release CO2]which would make them more economical and sustainable than competing technologies.

But there are still challenges ahead in terms of scalability, making materials that are chemically stable, and precisely controlling how and when they release the molecules they suck up from the environment. For example, we can already make MOFs at the scale of several tons, but we cannot yet make COFs in such large quantities. In a few years, I think we will become bigger. Another example: for better water harvesting, we need to optimize the way materials retain water – it can neither be too strong nor too weak.

We now also use artificial intelligence agents to optimize MOFs and COFs and make the design process as efficient as possible. It is, in general, easy to create a MOF or COF, but it can take a year to create one with specifically optimized properties. If an AI agent could do this faster, it would be transformational. I went into the lab and told everyone to try using big language models and we’ve already doubled the speed at which we can create new MOFs.

What uses of reticular chemistry do you think more people should be excited about?

Reticular chemistry is currently a huge field: millions of new MOFs can still be made and chemists behave a bit like children in a candy store. One interesting idea is to use MOFs to do what enzymes do when they speed up chemical reactions, a process called catalysis, which can help synthesize useful chemicals, for example in drug development. We have MOFs that can do what enzymes can do, but they might last and work longer than enzymes. This is ripe to be exploited for biological and therapeutic applications over the next decade.

But I think the next best use cases will come from “multivariate materials,” research that you don’t hear much about because it only happens in my lab. Here we want to create MOFs that do not have the same end-to-end structure, but contain extremely different environments within them. We can make them from different modules “decorated” with different compounds, so that inside the material there would be very different microenvironments that would make specific molecules do specific things. In experiments, we have already been able to exploit this to make materials that absorb gases more selectively and more efficiently. It is also a change in the mentality of chemists. Chemists are not used to thinking about making heterogeneous or uneven materials, but we want a very ordered skeleton for a material combined with very heterogeneous guts.

What makes you optimistic about the future of MOFs and COFs? “Miracle materials” have already existed.

We’ve only scratched the surface and we’re not short of ideas. The field has been growing since the 1990s. Often research interests decline over time, but that hasn’t happened here, and if you look at the growth of patents related to MOFs and COFs, you see an exponential increase there as well. People are still looking for ways to not only solve intellectual challenges in chemistry, but also to find new applications and uses for these materials. And I love how this work combines organic and inorganic chemistry into one field, and it now also incorporates engineering and AI. It has become more than just chemistry: this type of research constitutes a real scientific frontier.

I think we are experiencing a revolution. This isn’t always the case, but something special happens. We can design materials like we’ve never done before and connect them to uses like we’ve never done before.