Metal-organic frameworks structure scrutinised
2 Mar 2017 by qwqcdhhcbc.d qwqcdhhcbc.d
New high-sensitivity cameras have enabled researchers to better understand the atomic structure of metal-organic frameworks.
New high-sensitivity cameras have enabled researchers to better understand the atomic structure of metal-organic frameworks.
Metal-organic frameworks (MOFs) are hybrid porous materials useful for gas storage and separation as they can have bespoke pore sizes designed to contain or filter molecules of different sizes. MOFs are comprised of metal ions connected by organic ligands.Associate Professor of Chemical Science, Yu Han from the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, said: “To thoroughly understand the performance of metal-organic frameworks in various applications, we need to know their structures at the atomic level because their macroscopic behaviour is determined by their microscopic structure.”
High-resolution transmission electron microscopy (HRTEM) is used to visualise structures with atomic resolution; however, this method is unsuitable for observing MOFs because the electron beams destroy their structures. Researchers adapted HRTEM to use cutting-edge direct detection electron-counting cameras.
This enabled the scientists to acquire images with an electron ‘dose’ low enough to avoid damaging the MOFs’ structure. This was successfully used to investigate the properties of ZIF-8, a MOF which is made up of zinc ions connected by 2-methylimidazole linkers.
The image was resolved with a resolution of 0.21nm, allowing for individual columns of zinc atoms and organic linkers to be seen. The study was published in Nature Materials.