200 grams of this incredible powder can pull as much CO2 out of the air as a mature tree

Carbon capture and storage technologies have become crucial to addressing the growing challenge of climate change, particularly as carbon dioxide levels in the atmosphere continue to rise. While current carbon capture methods can efficiently trap carbon from concentrated sources like power plants, capturing CO2 from the atmosphere, where it is much less concentrated, poses a significant challenge.

Yet, scientists believe direct air capture (DAC) is essential to reverse the increase in atmospheric carbon dioxide, which has reached 426 parts per million (ppm)—50% higher than pre-Industrial Revolution levels. According to the Intergovernmental Panel on Climate Change (IPCC), DAC will be vital to achieving the global goal of limiting temperature rise to 1.5°C (2.7°F) above pre-industrial averages.

A groundbreaking new material developed by chemists at the University of California, Berkeley, may represent a major step forward in DAC technology.

This porous material, known as a covalent organic framework (COF), can capture CO2 from ambient air without breaking down due to water or other contaminants, a significant limitation of current DAC methods. The lead researcher, Omar Yaghi, professor of chemistry at UC Berkeley, and his team are optimistic about the potential of this new material to contribute to negative emissions.

"We took a powder of this material, put it in a tube, and passed Berkeley air—just outdoor air—into the material to see how it would perform," Yaghi explained. "It was beautiful. It cleaned the air entirely of CO2. Everything."

Yaghi’s team found that the material not only performed well in capturing carbon from the air, but it also outperformed other materials currently used in DAC systems. According to Yaghi, this new COF could be easily integrated into existing carbon capture systems that are currently being developed or deployed to reduce CO2 emissions from industrial sources and capture atmospheric carbon for underground storage.

In addition to its effectiveness, this material offers a compelling comparison to trees when it comes to capturing carbon. UC Berkeley graduate student Zihui Zhou, the first author of the research paper, highlighted the material’s impressive capacity.

Just 200 grams of the COF—less than half a pound—can capture 20 kilograms (44 pounds) of CO2 per year, equivalent to the carbon absorption of a mature tree. Zhou also emphasized the long-term impact of DAC technology in reversing the rise in atmospheric CO2 levels.

"Flue gas capture is a way to slow down climate change because you are trying not to release CO2 to the air," Zhou said. "Direct air capture is a method to take us back to like it was 100 or more years ago."

Today, atmospheric CO2 levels have exceeded 420 ppm, but experts project that this could rise to 500 or 550 ppm before effective flue gas capture is fully deployed. If the world hopes to reduce CO2 levels back to 400 or even 300 ppm, DAC systems will need to play a significant role.

The COF developed by Yaghi and his team builds on decades of research into porous materials for carbon capture. Yaghi, the inventor of both COFs and metal-organic frameworks (MOFs), has been working on such technologies since the 1990s, long before DAC became a widely recognized approach to climate mitigation. MOFs, which consist of metal atoms and organic molecules arranged in a crystalline structure, have proven effective for capturing gases, including carbon dioxide, but they have certain limitations.

One of Yaghi’s previous creations, MOF-808, showed great promise for capturing CO2. However, after hundreds of cycles of use, the MOFs began to degrade. The material’s instability under certain conditions, particularly when exposed to bases like amines (a group commonly used in carbon capture systems), limited its durability.

To address these issues, Yaghi and his colleagues set out to design a more stable material. Their new COF, called COF-999, is held together by strong covalent carbon-carbon and carbon-nitrogen bonds. Like MOFs, the COF’s pores are lined with amines, which increase the material’s capacity to bind CO2. The result is a material that is highly selective for CO2, water-stable, and capable of being reused for hundreds of cycles without degrading.

“Trapping CO2 from air is a very challenging problem,” Yaghi noted. “You need a material that has high carbon dioxide capacity, that’s highly selective, that’s water stable, oxidatively stable, recyclable, and scalable. It’s a tall order for a material.” Yaghi explained that most current systems rely on energy-intensive processes, such as bubbling exhaust gases through liquid amines, which require substantial energy to regenerate.

The COF-999 material meets many of the stringent requirements for DAC technology. When 400 ppm CO2 air is passed through the COF at room temperature and 50% humidity, it reaches half capacity in 18 minutes and fully fills within two hours. It releases CO2 when heated to just 60°C (140°F), making it much more energy-efficient than other systems. In terms of capacity, COF-999 can hold up to 2 millimoles of CO2 per gram, outperforming many other solid sorbents used for air capture.

One of the most remarkable aspects of COF-999 is its ability to withstand 100 adsorption-desorption cycles without any loss of capacity, a feat unmatched by other materials. Yaghi and his team believe that with further optimization, the material could be even more efficient. “It’s basically the best material out there for direct air capture,” Yaghi said.

Looking ahead, Yaghi is hopeful that artificial intelligence (AI) could help accelerate the development of even more advanced COFs and MOFs. By using AI to predict the optimal chemical conditions for creating new materials, researchers may be able to discover new solutions more quickly.

Yaghi, who serves as the scientific director of UC Berkeley’s Bakar Institute of Digital Materials for the Planet (BIDMaP), is already working on AI-driven approaches to design more cost-effective and scalable carbon capture materials.

"We’re very, very excited about blending AI with the chemistry that we’ve been doing," Yaghi said.

With innovations like COF-999, the future of carbon capture looks promising. These materials could play a pivotal role in reducing atmospheric CO2 levels and helping humanity reach its climate goals. As researchers continue to push the boundaries of what’s possible, the hope is that these advancements will lead to scalable, deployable solutions that can significantly mitigate the impacts of climate change.

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