UC Berkeley researchers have created a revolutionary metal-organic framework (MOF) capable of capturing CO2 from industrial exhaust at high temperatures, which could significantly impact carbon capture technology and help fight climate change.
In a groundbreaking development for carbon capture technology, scientists at the University of California, Berkeley have discovered a new material that can efficiently capture carbon dioxide from industrial exhaust streams at high temperatures. This innovation, which could significantly improve the feasibility of carbon capture in some of the most polluting industries, will be published in the upcoming issue of Science on Nov. 15, 2024.
Industrial plants, including those producing cement and steel, emit large amounts of CO2, a major greenhouse gas, at temperatures often exceeding 200 degrees Celsius (over 400 degrees Fahrenheit). Traditional carbon capture technologies using liquid amines operate efficiently only at lower temperatures, making them impractical for these high-temperature exhaust streams due to the need for substantial energy and water to cool the gases.
This discovery comes from UC Berkeley chemists, led by a team from the lab of Jeffrey Long, a UC Berkeley professor of chemistry, chemical and biomolecular engineering and of materials science and engineering, who have developed a type of metal-organic framework (MOF) that captures CO2 at temperatures up to 300 degrees Celsius (570 degrees Fahrenheit). The MOF, known as ZnH-MFU-4l, features zinc hydride sites that bind and release CO2 molecules effectively under extreme temperature conditions.
“A costly infrastructure is necessary to take these hot gas streams and cool them to the appropriate temperatures for existing carbon capture technologies to work,” co-first author Kurtis Carsch, a postdoctoral fellow at UC Berkeley, said in a news release. “Our discovery is poised to change how scientists think about carbon capture. We’ve found that a MOF can capture carbon dioxide at unprecedentedly high temperatures — temperatures that are relevant for many CO2-emitting processes. This was something that was previously not considered as possible for a porous material.”
Unlike traditional methods focusing on amine-based solutions, this new approach utilizes the inherent structural properties of MOFs. These frameworks consist of a porous, crystalline array of metal ions and organic linkers, providing a high density of sites to capture and release CO2.
“Our work moves away from the prevalent study of amine-based carbon capture systems and demonstrates a new mechanism for carbon capture in a MOF that enables high temperature operation,” added co-first author Rachel Rohde, a graduate student at UC Berkeley.
Under simulated conditions, the researchers have demonstrated that this MOF can capture hot CO2 from exhaust streams typical of cement and steel manufacturing, with concentrations ranging between 20% to 30%. The MOF also shows potential for capturing less concentrated emissions from natural gas power plants.
Removing CO2 from industrial emissions and storing it underground or repurposing it for fuels and other valuable chemicals is essential to reducing greenhouse gases that contribute to global warming and climate change. While renewable energy sources are reducing reliance on fossil fuel-burning power plants, industries heavily reliant on fossil fuels still need effective decarbonization strategies.
“We need to start thinking about the CO2 emissions from industries, like making steel and making cement, that are hard to decarbonize, because it’s likely that they’re still going to be emitting CO2, even as our energy infrastructure shifts more toward renewables,” added Rohde.
This research builds on more than a decade of work on CO2-adsorbing MOFs. Long’s previous developments have paved the way for innovations in CO2 capture, and this new breakthrough demonstrates the feasibility of high-temperature operations previously thought impossible.
“Because entropy favors having molecules like CO2 in the gas phase more and more with increasing temperature, it was generally thought to be impossible to capture such molecules with a porous solid at temperatures above 200 C,” Long said in the news release. “This work shows that with the right functionality — here, zinc hydride sites — rapid, reversible, high-capacity capture of CO2 can indeed be accomplished at high temperatures such as 300 C.”
The team’s future research aims to explore other potential gases that these MOFs can capture and to enhance their CO2 adsorption capacity further, marking a new direction in separation science that focuses on functional adsorbents capable of operating at high temperatures.
“We’re fortunate to have made this discovery, which has opened up new directions in separation science focused on the design of functional adsorbents that can operate at high temperatures,” added Carsch, who recently joined the Department of Chemistry at The University of Texas at Austin.
This breakthrough presents a promising solution for industries striving to reduce their carbon footprint and contributes to the global fight against climate change by making high-temperature CO2 capture more efficient and feasible.