Synthetic materials have 'world's highest' surface area
A team from Northwestern University has broken a new world record by creating two new synthetic materials with the greatest amount of surface area reported to date.
The new NU-109 and NU-110 materials belong to a class of crystalline nanostructure known as metal-organic frameworks (MOFs) that are promising vessels for natural gas storage for vehicles, catalysts and other sustainable materials chemistry.
"The materials' promise lies in their vast internal surface area," noted Omar Farha, research associate professor of chemistry in the Weinberg College of Arts and Sciences. "If the internal surface area of one NU-110 crystal the size of a grain of salt could be unfolded, the surface area would cover a desktop. Put another way, the internal surface area of one gram of NU-110 would cover one-and-a-half football fields."
Led by Farha, the research team synthesised, characterised, and computationally simulated the behaviour of the two MOFs that display the highest experimental surface areas of any porous material on record, 7,000 m2/g.
The extremely high surface area, which is normally not accessible due to solvent molecules that stay trapped within the pores, was achieved using a carbon dioxide activation technique. As opposed to heating, which can remove the solvent but also damage the MOF material, the carbon dioxide-based technique removes the solvent gently and leaves the pores completely intact.
The researchers are hoping the development will rapidly lead to further advances. MOFs are composed of organic linkers held together by metal atoms, resulting in a molecular cage-like structure. The team believes it may be able to more than double the surface area of the materials by using less bulky linker units in the materials' design.
