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Toward a smaller carbon footprint

Technology that takes carbon dioxide out of the atmosphere and turn it into valuable chemicals and fuels

Date:
October 3, 2018
Source:
University of Pittsburgh
Summary:
Researchers have made a breakthrough in carbon nanotube technology that removes carbon dioxide from the air and converts it into useful chemicals.
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Burning fossil fuels such as coal and natural gas releases carbon into the atmosphere as CO2while 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 CO2from 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.

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 CO2molecules slightly, taking them to a state in which they react with hydrogen more easily."

约翰逊的研究小组发表了他们的发现s in the Royal Society of Chemistry (RSC) journalCatalysis Science & Technology. The journal featured their work on its cover, illustrating the process of carbon dioxide and hydrogen molecules entering the MOF and exiting as CH2O2or 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 CO2molecules together so that they can form the new compound. In our previous work we have been able to activate H2by splitting two H atoms, but we have not been able to activate CO2until 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 CO2by 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 CO2does 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 CO2would be economically viable and would reduce the net amount of CO2in the atmosphere. "You could capture CO2from 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.

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Materialsprovided byUniversity of Pittsburgh.Note: Content may be edited for style and length.


Journal Reference:

  1. Jingyun Ye, Lin Li, J. Karl Johnson.The effect of topology in Lewis pair functionalized metal organic frameworks on CO2adsorption and hydrogenation.Catalysis Science & Technology, 2018; 8 (18): 4609 DOI:10.1039/c8cy01018h

Cite This Page:

University of Pittsburgh. "Toward a smaller carbon footprint: Technology that takes carbon dioxide out of the atmosphere and turn it into valuable chemicals and fuels." ScienceDaily. ScienceDaily, 3 October 2018. .
University of Pittsburgh. (2018, October 3). Toward a smaller carbon footprint: Technology that takes carbon dioxide out of the atmosphere and turn it into valuable chemicals and fuels.ScienceDaily. Retrieved June 29, 2023 from www.koonmotors.com/releases/2018/10/181003134458.htm
University of Pittsburgh. "Toward a smaller carbon footprint: Technology that takes carbon dioxide out of the atmosphere and turn it into valuable chemicals and fuels." ScienceDaily. www.koonmotors.com/releases/2018/10/181003134458.htm (accessed June 29, 2023).

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