Carbon Chemist

Tag: Metal-organic Frameworks

  • MOF-525 Can Capture and Convert CO2 Into Useful Chemicals

    MOF-525 Can Capture and Convert CO2 Into Useful Chemicals

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    By Jennifer McManamay, University of Virginia School of Engineering and Applied Science June 2, 2024

    Refinery Industrial Carbon Capture Concept Art

    Researchers have made a significant advancement in the practical application of a novel material known as MOF-525, a member of the metal-organic frameworks family, which shows great promise in carbon capture and conversion technologies. The team has developed a scalable manufacturing process using solution shearing techniques that allows MOF-525 to be applied in large areas, thus enhancing its effectiveness in capturing and converting carbon dioxide into commercially valuable chemicals. Credit: SciTechDaily.com

    Researchers at the University of Virginia have developed a scalable method for fabricating MOF-525, a material that can effectively capture and convert carbon dioxide into useful chemicals. This breakthrough offers a practical solution for large-scale applications in carbon capture and conversion, presenting significant environmental and energy benefits.

    Scientists have figured out how to take a miracle material, one capable of extracting value from captured carbon dioxide, and do what no one else has: make it practical to fabricate for large-scale application. Researchers at the University of Virginia School of Engineering and Applied Science conducted the study, which was published in ACS Applied Materials & Interfaces.

    The breakthrough from chemical engineering assistant professor Gaurav “Gino” Giri’s lab group has implications for the cleanup of the greenhouse gas, a major contributor to the climate change dilemma. It could also help solve the world’s energy needs.

    The Power of MOF-525

    The substance, called MOF-525, is in a class of materials called metal-organic frameworks.

    “If you can make these MOFs cover large areas, then new applications become possible, like making a membrane for carbon capture and electrocatalytic conversion all in one system,” Giri said.

    Electrocatalytic conversion creates a bridge from renewable energy sources to direct chemical synthesis, taking the burning of carbon dioxide-producing fossil fuels out of the equation.

    Gaurav Giri

    Assistant professor of chemical engineering Gaurav Giri. Credit: Tom Cogill

    Advancing Carbon Capture Solutions

    What gives MOFs superpowers is their ultra-porous, crystalline structures — 3D networks of minute nanoscale cavities that create vast internal surface area and act like a sponge — that can be designed to trap all sorts of chemical compounds.

    Giri’s group reasoned that starting with an inherently scalable synthesis technique — solution shearing — would better their odds. They had already had success shearing simpler MOFs.

    In Giri’s process, the MOF’s components are mixed in a solution, and then spread across a substrate with the shearing blade. As the solution evaporates, chemical linkages form the MOF as a thin film on the substrate. Applying MOF-525 in this way produces an all-in-one membrane for carbon trapping and conversion.

    Scaling Up for Greater Impact

    “The bigger the membrane, the more surface area you have for the reaction, and the more product you could get,” said Prince Verma, a December 2023 Ph.D. graduate from Giri’s lab. “With this process, you can increase the shearing blade width to whatever size you need.”

    The team targeted CO2 conversion to demonstrate their solution shearing approach because carbon capture is widely used to reduce industrial emissions or to remove it from the atmosphere — but at a cost to operators with minimal return on the investment: Carbon dioxide has little commercial value and most often winds up stored indefinitely underground.

    However, with minimal energy input, using electricity to catalyze a reaction, MOF-525 can take away an oxygen atom to make carbon monoxide — a chemical that is valuable for manufacturing fuels, pharmaceuticals, and other products.

    UVA’s Commitment to Green Energy

    The process of accelerating reactions through catalysis, especially electrocatalysis, which consumes less energy than reactions driven by heat or pressure, is essential to a green-energy future — so much so that UVA invested $60 million in catalysis study as part of UVA’s Grand Challenges Investments.

    For that expertise, Giri collaborated with UVA associate professor of chemistry Charles W. Machan.

    “The materials from Gino’s lab help us understand how to enable new, scalable technologies for capture and conversion, which we’re going to need to address the environmental challenges posed by current carbon dioxide concentrations in the atmosphere and rate of emissions,” Machan said. 

    The researchers published their findings in the American Chemical Society journal Applied Materials and Interfaces.

    Reference: “Solution Shearing of Zirconium (Zr)-Based Metal–Organic Frameworks NU-901 and MOF-525 Thin Films for Electrocatalytic Reduction Applications” by Prince K. Verma, Connor A. Koellner, Hailey Hall, Meagan R. Phister, Kevin H. Stone, Asa W. Nichols, Ankit Dhakal, Earl Ashcraft, Charles W. Machan and Gaurav Giri, 13 November 2023, ACS Applied Materials & Interfaces.
    DOI: 10.1021/acsami.3c12011

    Also contributing to the work were Connor A. Koellner, Hailey Hall, Meagan R. Phister, Kevin H. Stone, Asa W. Nichols, Ankit Dhakal and Earl Ashcraft.

    The research was supported by the UVA Environmental Institute; the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Catalysis Science Program; the Nanoscale Materials Characterization Facility at UVA; and the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory.



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  • Chameleon Coatings for Smarter, Cooler Living Spaces

    Chameleon Coatings for Smarter, Cooler Living Spaces

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    Smart Windows Art Concept

    Researchers have developed a new type of electrochromic film using metal-organic frameworks (MOFs) that switches colors rapidly to control light and heat transmission. This film can transition between colorless, green, and red states with simple voltage changes, holding potential for use in smart windows and other intelligent devices. Credit: SciTechDaily.com

    A new electrochromic film using MOFs quickly switches colors for effective light and heat management, showing promise for smart windows and other adaptive technologies.

    Advances in electrochromic coatings may bring us closer to environmentally friendly ways to keep inside spaces cool. Like eyeglasses that darken to provide sun protection, the optical properties of these transparent films can be tuned with electricity to block out solar heat and light. Now, researchers in ACS Energy Letters report demonstrating a new electrochromic film design based on metal-organic frameworks (MOFs) that quickly and reliably switch from transparent to glare-diminishing green to thermal-insulating red.

    Electrochromic Films Window Sunglasses

    This electrochromic film’s color and optical properties change when the electric potential goes from 0 to 0.8 to 1.6 volts: Green helps reduce glare, and red enhances thermal insulation. Credit: Adapted from ACS Energy Letters 2024, DOI: 10.1021/acsenergylett.4c00492

    Innovations in MOF-Based Electrochromic Films

    Hongbo Xu and colleagues used MOFs in their electrochromic film because of the crystalline substances’ abilities to form thin films with pore sizes that can be customized by changing the length of the organic ligand that binds to the metal ion. These features enable improved current flow, more precise control over colors, and durability.

    In demonstrations, Xu’s MOF electrochromic film took 2 seconds to switch from colorless to green with an electric potential of 0.8 volts, and 2 seconds to switch to dark red with 1.6 V. The film maintained the green or red color for 40 hours when the potential dropped, unless a reverse voltage was applied to return the film to its transparent state.

    The film also performed reliably through 4,500 cycles of switching from colored to clear. With further optimization, the researchers say their tunable coatings could be used in smart windows that regulate indoor temperatures, as well as in smaller scale intelligent optical devices and sensors.

    Broader Developments in Electrochromic Technologies

    In addition to Xu’s MOF-based electrochromic film, several other research groups have reported electrochromic coating designs, including a UV-blocking but visually transparent radiative cooling film, a colorful plant-based film that gets cooler when exposed to sunlight, and a temperature-responsive film that turns darker in cold weather and lighter when it’s hot.

    Reference: “Biphenyl Dicarboxylic-Based Ni-IRMOF-74 Film for Fast-Switching and High-Stability Electrochromism” 29 May 2024, ACS Energy Letters.
    DOI: 10.1021/acsenergylett.4c00492

    The authors acknowledge funding from the National Natural Science Foundation of China, Natural Science Foundation of Heilongjiang Province, and the Scientific Research Startup Project of Quzhou University.



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  • Porous isoreticular non-metal organic frameworks

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  • MIT Unveils Game-Changing Sensor for Toxic Gas Detection

    MIT Unveils Game-Changing Sensor for Toxic Gas Detection

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    By David L. Chandler, Massachusetts Institute of Technology May 17, 2024

    Toxic Waste Warning Sign

    MIT researchers have developed a novel gas detection system that combines metal-organic frameworks with a durable polymer to enable continuous and sensitive monitoring of toxic gases like nitrogen dioxide. This new sensor can detect low

    A breakthrough in gas detection technology at MIT combines high sensitivity and continuous monitoring. The material could be made as a thin coating to analyze air quality in industrial or home settings.

    Most systems designed to detect toxic gases in industrial or domestic environments are limited to single or minimal uses. Researchers at MIT, however, have created a detector capable of providing continuous, low-cost monitoring of these gases.

    The new system combines two existing technologies, bringing them together in a way that preserves the advantages of each while avoiding their limitations. The team used a material called a metal-organic framework, or MOF, which is highly sensitive to tiny traces of gas but whose performance quickly degrades, and combined it with a polymer material that is highly durable and easier to process, but much less sensitive.

    The results are reported today in the journal Advanced Materials, in a paper by MIT professors Aristide Gumyusenge, Mircea Dinca, Heather Kulik, and Jesus del Alamo, graduate student Heejung Roh, and postdocs Dong-Ha Kim, Yeongsu Cho, and Young-Moo Jo.

    MOF Toxic Gas Detector

    Researchers at MIT have developed a detector that could provide continuous monitoring for the presence of toxic gases, at low cost. The team used a material called a metal-organic framework, or MOF (pictured as the black lattice), which is highly sensitive to tiny traces of gas but whose performance quickly degrades. They combined the MOF with a polymer material, shown as the teal translucent strands, that is highly durable but much less sensitive. Credit: Courtesy of the researchers

    Innovative Material Combination

    Highly porous and with large surface areas, MOFs come in a variety of compositions. Some can be insulators, but the ones used for this work are highly electrically conductive. With their sponge-like form, they are effective at capturing molecules of various gases, and the sizes of their pores can be tailored to make them selective for particular kinds of gases. “If you are using them as a sensor, you can recognize if the gas is there if it has an effect on the resistivity of the MOF,” says Gumyusenge, the paper’s senior author and the Merton C. Flemings Career Development Assistant Professor of Materials Science and Engineering.

    The drawback for these materials’ use as detectors for gases is that they readily become saturated, and then can no longer detect and quantify new inputs. “That’s not what you want. You want to be able to detect and reuse,” Gumyusenge says. “So, we decided to use a polymer composite to achieve this reversibility.”

    The team used a class of conductive polymers that Gumyusenge and his co-workers had previously shown can respond to gases without permanently binding to them. “The polymer, even though it doesn’t have the high surface area that the MOFs do, will at least provide this recognize-and-release type of phenomenon,” he says.

    MOF Toxic Gas Detector Setup

    Researchers demonstrated the material’s ability to detect nitrous oxide, a toxic gas produced by many kinds of combustion, in a small lab-scale device. After 100 cycles of detection, the material was still maintaining its baseline performance within a margin of about 5 to 10 percent, demonstrating its long-term use potential. Here is the layout of the sensing setup. Credit: Courtesy of the researchers

    Enhanced Sensing Capabilities

    The team combined the polymers in a liquid solution along with the MOF material in powdered form, and deposited the mixture on a substrate, where they dry into a uniform, thin coating. By combining the polymer, with its quick detection capability, and the more sensitive MOFs, in a one-to-one ratio, he says, “suddenly we get a sensor that has both the high sensitivity we get from the MOF and the reversibility that is enabled by the presence of the polymer.”

    The material changes its electrical resistance when molecules of the gas are temporarily trapped in the material. These changes in resistance can be continuously monitored by simply attaching an ohmmeter to track the resistance over time. Gumyusenge and his students demonstrated the composite material’s ability to detect nitrogen dioxide, a toxic gas produced by many kinds of combustion, in a small lab-scale device. After 100 cycles of detection, the material was still maintaining its baseline performance within a margin of about 5 to 10 percent, demonstrating its long-term use potential.

    In addition, this material has far greater sensitivity than most presently used detectors for nitrogen dioxide, the team reports. This gas is often detected after the use of stove ovens. And, with this gas recently linked to many asthma cases in the U.S., reliable detection in low concentrations is important. The team demonstrated that this new composite could detect, reversibly, the gas at concentrations as low as 2 parts per million.

    Applications and Future Directions

    While their demonstration was specifically aimed at nitrogen dioxide, Gumyusenge says, “We can definitely tailor the chemistry to target other volatile molecules,” as long as they are small polar analytes, “which tend to be most of the toxic gases.”

    Besides being compatible with a simple hand-held detector or a smoke-alarm type of device, one advantage of the material is that the polymer allows it to be deposited as an extremely thin uniform film, unlike regular MOFs, which are generally in an inefficient powder form. Because the films are so thin, there is little material needed and production material costs could be low; the processing methods could be typical of those used for industrial coating processes. “So, maybe the limiting factor will be scaling up the synthesis of the polymers, which we’ve been synthesizing in small amounts,” Gumyusenge says.

    “The next steps will be to evaluate these in real-life settings,” he says. For example, the material could be applied as a coating on chimneys or exhaust pipes to continuously monitor gases through readings from an attached resistance monitoring device. In such settings, he says, “we need tests to check if we truly differentiate it from other potential contaminants that we might have overlooked in the lab setting. Let’s put the sensors out in real-world scenarios and see how they do.”

    Reference: “Robust Chemiresistive Behavior in Conductive Polymer/MOF Composites” by Heejung Roh, Dong-Ha Kim, Yeongsu Cho, Young-Moo Jo, Jesús A. del Alamo, Heather J. Kulik, Mircea Dincă and Aristide Gumyusenge, 17 April 2024, Advanced Materials.
    DOI: 10.1002/adma.202312382

    The work was supported by the MIT Climate and Sustainability Consortium (MCSC), the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) at MIT, and the U.S. Department of Energy.



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