Scientists squeeze more out of metal-organic framework

Jan 12, 2010
Argonne National Lab scientist Karena Chapman holds up a wafer of metal organic framework ZIF-8 with its structure displayed on the computer screen. Chapman along with collaborators Peter Chupas and Gregory Halder were able to change the structure of a metal organic framework at pressures low enough for large scale industrial applications.

(PhysOrg.com) -- Scientists at the U.S. Department of Energy's Argonne National Laboratory have discovered a new route to transform the structure of porous materials at industrially-accessible high pressures.

“Normally, these materials will spring back to their original structure after they have been compressed, almost like a spring, but above a certain pressure this material adopts a new structure,” Argonne scientist Karena Chapman said. “It is a related structure, but it is as if when we compressed the spring, it bounced back to a different shape.”

ZIF-8 is a commercially available metal-organic framework (MOF) with molecular-scale pores that can have valuable catalytic applications. Chapman, along with scientists Gregory Halder and Peter Chupas, used the Advanced Photon Source’s high-focused X-ray beams to observe the structure of the compound after it withstood varying degrees of pressure. The structural transition was found to occur at relatively modest pressures — pressures that can be achieved on the larger scales needed to test how the change in structure affects the compound's functional behavior.

Gas uptake measurements, carried out within the Materials Science Division, revealed that the material’s porosity was modified for the new structure. This could be used to optimize its performance for specific applications in areas such as for fuel cells. This discovery shows that by exerting pressure on MOFs through the pelletization process, researchers can modify the compound's structure and storage property.

While this type of structural change has been seen in traditional porous materials (e.g., zeolites) at much higher pressures, the structural changes in the MOF material occur at lower pressures and consequently, this modification can be more readily scaled up to industrial levels.

The next step is for the scientists to examine the mechanism of the structural change and how this modification process can be most effectively exploited for molecular storage and separation applications.

Explore further: Technique simplifies the creation of high-tech crystals

More information: A paper about this discovery was recently published in the Journal of the American Chemical Society.

Related Stories

Innovation in Nanoporous Chemistry

Sep 30, 2005

Science researchers from the University of Versailles (France), in collaboration with the ID31 beam line at the European Synchrotron Radiation Facility (ESRF), report their progress in the design and characterisation of microporous ...

New hydrogen-storage method discovered

Nov 22, 2009

Scientists at the Carnegie Institution have found for the first time that high pressure can be used to make a unique hydrogen-storage material. The discovery paves the way for an entirely new way to approach ...

Recommended for you

Timely arrival of Pharao space clock

1 hour ago

ESA has welcomed the arrival of Pharao, an important part of ESA's atomic clock experiment that will be attached to the International Space Station in 2016.

Physicists discuss quantum pigeonhole principle

Jul 26, 2014

The pigeonhole principle: "If you put three pigeons in two pigeonholes at least two of the pigeons end up in the same hole." So where's the argument? Physicists say there is an important argument. While the ...

First in-situ images of void collapse in explosives

Jul 25, 2014

While creating the first-ever images of explosives using an x-ray free electron laser in California, Los Alamos researchers and collaborators demonstrated a crucial diagnostic for studying how voids affect ...

User comments : 0