Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > An open-and-shut case: The adsorption of gases onto the surface of flexible porous networks is a critical stage in the transformation of the porous st

Figure 1: Selective gas adsorption of flexible PCPs. The onset pressure for the gate-opening process is lower for oxygen (O2) than for nitrogen (N2) and argon (Ar). As a result, within a certain pressure range, only oxygen adsorbs.
Figure 1: Selective gas adsorption of flexible PCPs. The onset pressure for the gate-opening process is lower for oxygen (O2) than for nitrogen (N2) and argon (Ar). As a result, within a certain pressure range, only oxygen adsorbs.

Abstract:
Researchers in Japan have revealed important information about why the threshold of gas pressure required for the structural transformation of flexible, three-dimensional molecular networks known as porous coordination polymers (PCPs) varies for different gases. The ability of PCPs to reversibly change their structure and properties on adsorption of ‘guest' gas molecules has received considerable attention in recent years owing to their commercial potential in gas separation and sensing applications.

An open-and-shut case: The adsorption of gases onto the surface of flexible porous networks is a critical stage in the transformation of the porous st

Japan | Posted on September 12th, 2008

Flexible PCPs exist in two forms: a closed phase, in which guests, such as oxygen molecules, are unable to penetrate the structure; and an adsorbed phase that allows sorption of oxygen into the structure. Transformation from the closed to the adsorbed phase, which results in opening the ‘gates' to structural channels, is guest-induced and occurs when the pressure of the gas—defined as Pgo—is sufficient.

The research team, led by Susumu Kitagawa and including researchers from the RIKEN SPring-8 Center in Harima and from Kyoto, Okayama and Osaka-Prefecture universities, has used a kinetic study to show why the value of the threshold pressure required for the initially closed structure to become accessible is different for similar gases1. Much of the commercial interest sparked in these materials has arisen from the difference of sorption behavior, that is, the difference in Pgo for similar gases.

The flexible PCP synthesized by the team is formed from cadmium ions and organic ligands and shows that the value of Pgo increases in the order of oxygen, argon and nitrogen and so, at low pressures, only oxygen is adsorbed (Fig. 1).

The researchers believe that their kinetic investigation of the structural transformation should further our knowledge and hence, allow the gas adsorption performance of PCPs to be fine-tuned.

According to RIKEN team-member Masakazu Higuchi, an ‘intermediate phase' exists at the point of gate-opening and, it is the formation kinetics of this intermediate that determines Pgo. Moreover, the kinetic behavior suggests that the gate-opening process is attributable to condensation of the adsorbate on the surface of the crystal, indicating that surface chemistry, rather than crystal structure analysis, needs to be probed to fully understand the gate-opening process.

The team hopes to investigate the process further by observing the surface using microscopic techniques and, in the long-term future, it may be possible to modify the crystal surface and hence, create a new mechanism for adsorption.
Reference

1. Tanaka, D., Nakagawa, K., Higuchi, M., Horike, S., Kubota, Y., Kobayashi, T. C., Takata, M. & Kitagawa, S. Kinetic gate-opening process in a flexible porous coordination polymer. Angewandte Chemie International Edition 47, 3914-3918 (2008). | article |

####

For more information, please click here

Copyright © Riken

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Solid state physics: Quantum matter stuck in unrest August 1st, 2015

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Kalam: versatility personified August 1st, 2015

Chemistry

March 2016; 6th Int'l Conference on Nanostructures in Iran July 29th, 2015

Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team July 29th, 2015

'Seeing' molecular interactions could give boost to organic electronics July 28th, 2015

Quantum networks: Back and forth are not equal distances! July 28th, 2015

Discoveries

Solid state physics: Quantum matter stuck in unrest August 1st, 2015

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Heating and cooling with light leads to ultrafast DNA diagnostics July 31st, 2015

Announcements

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Harris & Harris Group Portfolio Company, HZO, Announces Partnerships with Dell and Motorola August 1st, 2015

Advances and Applications in Biosensing, Sensor Power, and Sensor R&D to be Covered at Sensors Global Summit August 1st, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project