University of Pittsburgh researchers make a breakthrough in carbon nanotube technology that removes carbon dioxide from the air and converts it into useful chemicals
Burning fossil fuels such as coal and natural gas releases carbon into the atmosphere as CO2 while the production of methanol and other valuable fuels and chemicals requires a supply of carbon. There is currently no economically or energy efficient way to collect CO2 from the atmosphere and use it to produce carbon-based chemicals, but researchers at the University of Pittsburgh Swanson School of Engineering have just taken an important step in that direction.
From the left, a mixture of gases, including CO2 (red and gray), N2 (blue), and H2 (white) are exposed to the nanoporous metal-organic framework designed by the Johnson group. Only the CO2 and H2 enter the MOF, which rejects the N2. The catalytic sites within the framework convert the CO2 to formic acid (red, gray and white), a chemical precursor to methanol
Credit: Swanson School of Engineering/Johnson Group
The team worked with a class of nanomaterials called metal-organic frameworks or "MOFs," which can be used to take carbon dioxide out of the atmosphere and combine it with hydrogen atoms to convert it into valuable chemicals and fuels. Karl Johnson, the William Kepler Whiteford Professor in the Swanson School's Department of Chemical and Petroleum Engineering, led the research group as principal investigator.
"Our ultimate goal is to find a low-energy, low-cost MOF capable of separating carbon dioxide from a mixture of gases and prepare it to react with hydrogen," says Dr. Johnson. "We found a MOF that could bend the CO2 molecules slightly, taking them to a state in which they react with hydrogen more easily."
The Johnson Research Group published their findings in the Royal Society of Chemistry (RSC) journal Catalysis Science & Technology (DOI: 10.1039/c8cy01018h). The journal featured their work on its cover, illustrating the process of carbon dioxide and hydrogen molecules entering the MOF and exiting as CH2O2 or formic acid--a chemical precursor to methanol. For this process to occur, the molecules must overcome a demanding energy threshold called the hydrogenation barrier.
Dr. Johnson explains, "The hydrogenation barrier is the energy needed to add two H atoms to CO2, which transforms the molecules into formic acid. In other words, it is the energy needed to get the H atoms and the CO2 molecules together so that they can form the new compound. In our previous work we have been able to activate H2 by splitting two H atoms, but we have not been able to activate CO2 until now."
The key to reducing the hydrogenation barrier was to identify a MOF capable of pre-activating carbon dioxide. Pre-activation is basically preparing the molecules for the chemical reaction by putting it into the right geometry, the right position, or the right electronic state.
The MOF they modeled in their work achieves pre-activation of CO2 by putting it into a slightly bent geometry that is able to accept the incoming hydrogen atoms with a lower barrier.
Another key feature of this new MOF is that it selectively reacts with hydrogen molecules over carbon dioxide, so that the active sites are not blocked by CO2.
"We designed a MOF that has limited space around its binding sites so that there is not quite enough room to bind CO2, but there is still plenty of room to bind H2, because it is so much smaller. Our design ensures that the CO2 does not bind to the MOF but instead is free to react with the H molecules already inside the framework," says Dr. Johnson.
Dr. Johnson believes perfecting a single material that can both capture and convert CO2 would be economically viable and would reduce the net amount of CO2 in the atmosphere.
"You could capture CO2 from flue gas at power plants or directly from the atmosphere," he says. "This research narrows our search for a very rare material with the ability to turn a hypothetical technology into a real benefit to the world."
The Pitt Center for Research Computing contributed computing resources.
About the Johnson Research Group
The Johnson Research Group at the University of Pittsburgh uses atomistic modeling to tackle fundamental problems over a wide range of subject areas in chemical engineering, including the molecular design of nanoporous sorbents for the capture of carbon dioxide, the development of catalysts for conversion of carbon dioxide into fuels, the transport of gases and liquids through carbon nanotube membranes, the study of chemical reaction mechanisms, the development of CO2-soluble polymers and CO2 thickeners, and the study of hydrogen storage with complex hydrides.
About Dr. Johnson
Karl Johnson is an Associate Director of the Center for Research Computing and a member of the Pittsburgh Quantum Institute. He received his B.S. and M.S. in chemical engineering from Brigham Young University, and PhD in chemical engineering with a minor in computer science from Cornell University.
Matt Cichowicz | EurekAlert!
Quality control in immune communication: Chaperones detect immature signaling molecules in the immune system
20.09.2019 | Technische Universität München
Moderately Common Plants Show Highest Relative Losses
20.09.2019 | Universität Rostock
How long the battery of your phone or computer lasts depends on how many lithium ions can be stored in the battery's negative electrode material. If the battery runs out of these ions, it can't generate an electrical current to run a device and ultimately fails.
Materials with a higher lithium ion storage capacity are either too heavy or the wrong shape to replace graphite, the electrode material currently used in...
To process information, photons must interact. However, these tiny packets of light want nothing to do with each other, each passing by without altering the...
Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.
The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.
At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.
Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...
Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....
19.09.2019 | Event News
10.09.2019 | Event News
04.09.2019 | Event News
20.09.2019 | Life Sciences
20.09.2019 | Life Sciences
20.09.2019 | Life Sciences