Nobel laureate Omar Yaghi says his invention will change the world

Civilizations name their ages by materials. At school we learn about the Stone Age, the Bronze Age – and we are currently in a silicon age characterized by computers and telephones. What can define the next age? Omar Yaghi of the University of California, Berkeley, believes a family of materials he helped pioneer in the 1990s has a good chance. They are metal-organic frameworks (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 frameworks (COFs), are crystalline materials, but what sets them apart is their incredible porosity. In 1999, Yaghi and colleagues made a splash when they synthesized a zinc-based material called MOF-5 that was so full of pores that a few grams of it had an inner surface comparable to a football field (see diagram below). The inside of the material was actually much larger than the outside.

For decades, Yaghi has been at the forefront of creating new MOFs and COFs, a discipline known as reticular chemistry, and discovering how useful they can be. Because other molecules can be sucked into these materials’ rich pores, they prove adept at harvesting water from dry desert air, absorbing carbon dioxide from the atmosphere, and much more. Yaghi spoke with New Scientist about why he is optimistic about this work, the past, present and future of reticular chemistry—and why he believes the age of these materials is dawning.

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

Omar Yaghi: When we started working with MOFs, we didn’t think we were addressing 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 this was a truly formidable chemistry challenge. For many people it was taken as an article of faith that this would not work, that it was a waste of time to pursue it.

Why did it seem so impossible to design materials in this way?

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

It’s a bit like asking a room of children to make a perfect circle: it takes hard work, and when they do, they can still dissociate or “untie” their hands and then take too long to complete the circle again. To put it another way, we tried to do what nature does when it crystallizes diamonds over billions of years – but in one day. But I knew deep down that anything can be crystallized if you know how.

IIn 1999, your instincts were proven right and your team reported on the synthesis of MOF-5which was exceptionally stable. Did you foresee that a material like that 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 having the molecules in the mix was absolutely critical to modulating the tendency towards disorder. Thousands of researchers have used this method since.

In the beginning I was just excited to make beautiful crystals. Then we saw their beautiful properties and were able to say, “Wow, what can we do with this?” And once you know how much porosity these materials have, you immediately think about capturing gases. These materials include spaces where a molecule of water or carbon dioxide or something else can sit.

Tell me about how you think about creating 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 master dish in so few steps and only use healthy ingredients. This philosophy also played into my chemistry. In other words, I want to keep the process simple and only use the chemicals we really need.

The first step is to select the backbone of the material. The second determines the size of the pores. You can also do chemistry on the skeleton and add molecules to it, to help trap other compounds into the pores. The third step is to allow carbon dioxide or whatever you have built the material to be sucked in. That’s how simple and complex the process is.

What kind of new technology has this process allowed you to pursue?

When you first learn to design materials at the molecular level, it is the ultimate achievement, a geological shift. My vision, and the vision for the company I founded in 2020, Atoco, is to go from the molecule to society, to look at places where there is no material for some task or it does poorly, and then rationally design a better one. As we get better at crafting materials, we will improve community standards.

In 2024, we reported the best material yet for capturing carbon dioxide, called COF-999. It captures it from air, and we tested it for more than 100 cycles of capturing (expelling) carbon dioxide here at Berkeley. Atoco aims to use reticular materials such as COF-999 to build carbon capture modules that can work in industrial settings, but also in residential buildings.

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

There are other technologies that can capture water, such as devices that condense atmospheric vapors, and there are other devices that can also capture CO2. How do MOFs and COFs compare?

We have so much control over the chemistry that we can make our devices in a sustainable way. They can work for many, many years, and at the end of the journey to the MOF part of the device, you can disassemble it in water in such a way that no MOF escapes into the environment. So in a world where MOFs are scaled to multi-ton levels 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 sunlight from the environment to make water harvesters release water. For carbon capture devices, we can also use waste heat from industrial processes (to make them release CO2), which will make them more economical and sustainable than competing technologies.

But there are still challenges with scalability, making materials chemically stable and having precise control over how and when they release the molecules that they absorb from the environment. For example, we can already make MOFs on a ton scale, but we cannot yet make COFs in such large quantities. In a few years I suspect we will be bigger. As another example, for even better water harvesting, we need to optimize how materials retain water – it cannot be too strong or too weak.

We now also use artificial intelligence agents to help optimize MOFs and COFs and make the design process as efficient as possible. It is generally easy to make a MOF or a COF, but it can take a year to make one with specifically optimized properties. If an AI agent can do it faster, it will be transformative. I went into the lab and told everyone to try using large language models, and we’ve already doubled the speed of making some new MOFs.

What is the use of reticular chemistry that 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 kids in a candy store. An attractive idea is to use MOFs to do what enzymes do when they speed up chemical reactions, a process called catalysis, which could help synthesize useful chemicals, for example in drug development. We have MOFs that can do what enzymes can do, but they can last and work longer than enzymes. This is ripe to be exploited for biological applications, for therapeutic agents in the next decade or so.

But I think the next best use cases will come from “multivariate materials,” which is 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 structure throughout, but have massively different environments in them. We can make them from different modules that are “decorated” with different compounds, so inside the material there will be very different microenvironments that will make specific molecules do specific things. In experiments, we have already been able to exploit this to create materials that absorb gases more selectively and efficiently. This is also a shift in the mindset of chemists. Chemists are not used to thinking about making heterogeneous or non-uniform 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 come and gone before.

We have only scratched the surface here and are not short of ideas. The field has expanded since the 1990s. Research interests often decrease over time, but that has not happened here, and if you look at the growth in patents related to MOF and COF, you also see an exponential increase there. People continue to see ways to not only solve intellectual challenges in chemistry, but to find new applications and uses for these materials. And I love how this work combines organic and inorganic chemistry into one field, and now also brings in engineering and AI. It has become more than chemistry: this kind of research is a real scientific frontier.

I think we are going through a revolution. It doesn’t always feel like it, but something special is going on. We can design materials that we have never done before and connect them to uses that we have never done before.