Nav: Home

Investigating a thermal challenge for MOFs

August 11, 2020

To the naked eye, metal organic frameworks (MOFs) look a little like sand. But if you zoom in, you will see that each grain looks and acts more like a sponge--and serves a similar purpose. MOFs are used to absorb and hold gases, which is useful when trying to filter toxic gases out of the air or as a way to store fuel for natural gas- or hydrogen gas-powered engines.

New research led by an interdisciplinary team across six universities examines heat transfer in MOFs and the role it plays when MOFs are used for storing fuel. Corresponding author Christopher Wilmer, William Kepler Whiteford Faculty Fellow and assistant professor of chemical and petroleum engineering at the University of Pittsburgh's Swanson School of Engineering, coauthored the work with researchers at Carnegie Mellon University, the University of Virginia, Old Dominion University, Northwestern University, and the Karlsruhe Institute of Technology in Karlsruhe, Germany. The findings were recently published in Nature Communications.

"One of the challenges with using MOFs for fuel tanks in cars is that you have to be able to fill up in a few minutes or less," explains Wilmer. "Unfortunately, when you quickly fill these MOF-based tanks with hydrogen or natural gas they get very hot. It's not so much a risk of explosion--though there is one--but the fact that they can't store much gas when they're hot. The whole premise of using them to store a lot of gaseous fuel only works at room temperature. For other industrial applications you face a similar problem - whenever gases are loaded quickly the MOFs become hot and no longer work effectively."

In other words, for MOFs to be useful for these applications, they would need to be kept cool. This research looked at thermal transport in MOFs, to explore how quickly they can shed excess heat, and the group found some surprising results.

"When you take these porous materials, which to begin with are thermally insulating, and you fill them with gas, it appears that they become even more insulating. This is surprising because usually, empty pockets like those in insulation or double-paned windows provide good thermal insulation," explains Wilmer. "By taking porous materials and filling them, thereby removing those gaps, you would expect the thermal transport to improve, making it more thermally conductive. The opposite happens; they become more insulating."

To reach their conclusion, researchers conducted two simultaneous experiments using two different methods and MOFs synthesized in two different labs. Both groups observed the same trend: that the MOFs become more insulated when filled with adsorbates. Their experimental findings were also validated by atomistic simulations at Pitt in collaboration with Carnegie Mellon University.

"Our work indicates potential challenges ahead for the use of MOFs outside of research labs, but that is a necessary step in the process," says Alan McGaughey, professor of mechanical engineering at Carnegie Mellon. "As these materials advance toward broad, real-world usage, researchers will need to continue investigating once-overlooked properties of these materials, like thermal transport, and find the best way to use them to fit our needs."
-end-
The paper, "Observation of Reduced Thermal Conductivity in a Metal-Organic Framework," (DOI: 10.1038/s41467-020-17822-0) was published in Nature Communications. Coauthors include Hasan Babaei (Pitt), Mallory E. DeCoster (UVA), Minyoung Jeong (CMU), Zeinab M. Hassan (KIT), Timur Islamoglu (Northwestern), Helmut Baumgart (Old Dominion), Alan J. H. McGaughey (CMU), Redel Engelbert (KIT), Omar K. Farha (Northwestern), Patrick E. Hopkins (UVA), Jonathan A. Malen (CMU), and Christopher E. Wilmer.

Acknowledgements

H.B. and C.E.W. gratefully acknowledge support from the National Science Foundation (NSF), awards CBET-1804011 and OAC-1931436, and also thank the Center for Research Computing (CRC) at the University of Pittsburgh for providing computational resources. J.A.M. gratefully acknowledges support from the Army Research Office, grant W911NF-17-1-0397. A.J.H.M. gratefully acknowledges support from the NSF, award DMR-1507325. O.K.F. gratefully acknowledges support from the Defense Threat Reduction Agency, HDTRA1?18?1?0003. P.E.H. appreciates support from the Army Research Office, Grant. No. W911NF-16-1-0320. Financial support by Deutsche Forschungsgemeinschaft (DFG) within the COORNET Priority Program (SPP 1928) is gratefully acknowledged by E.R. and He.B. (Helmut Baumgart). Z.M.H. acknowledges financial support from the Egyptian Mission Foundation. We would also like to thank Ran Cao for collecting additional PXRD data for this study.

University of Pittsburgh

Related Engineering Articles:

Re-engineering antibodies for COVID-19
Catholic University of America researcher uses 'in silico' analysis to fast-track passive immunity
Next frontier in bacterial engineering
A new technique overcomes a serious hurdle in the field of bacterial design and engineering.
COVID-19 and the role of tissue engineering
Tissue engineering has a unique set of tools and technologies for developing preventive strategies, diagnostics, and treatments that can play an important role during the ongoing COVID-19 pandemic.
Engineering the meniscus
Damage to the meniscus is common, but there remains an unmet need for improved restorative therapies that can overcome poor healing in the avascular regions.
Artificially engineering the intestine
Short bowel syndrome is a debilitating condition with few treatment options, and these treatments have limited efficacy.
Reverse engineering the fireworks of life
An interdisciplinary team of Princeton researchers has successfully reverse engineered the components and sequence of events that lead to microtubule branching.
New method for engineering metabolic pathways
Two approaches provide a faster way to create enzymes and analyze their reactions, leading to the design of more complex molecules.
Engineering for high-speed devices
A research team from the University of Delaware has developed cutting-edge technology for photonics devices that could enable faster communications between phones and computers.
Breakthrough in blood vessel engineering
Growing functional blood vessel networks is no easy task. Previously, other groups have made networks that span millimeters in size.
Next-gen batteries possible with new engineering approach
Dramatically longer-lasting, faster-charging and safer lithium metal batteries may be possible, according to Penn State research, recently published in Nature Energy.
More Engineering News and Engineering Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.