Scientists from the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have taken the first images of carbon dioxide molecules within a molecular cage – part of a highly porous nanoparticle known as a MOF, or metal-organic framework, with great potential for separating and storing gases and liquids.
The images, made at the Stanford-SLAC Cryo-EM Facilities, show two configurations of the CO2 molecule in its cage, in what scientists call a guest-host relationship; reveal that the cage expands slightly as the CO2 enters; and zoom in on jagged edges where MOF particles may grow by adding more cages.
“This is a groundbreaking achievement that is sure to bring unprecedented insights into how these highly porous structures carry out their exceptional functions, and it demonstrates the power of cryo-EM for solving a particularly difficult problem in MOF chemistry,” said Omar Yaghi, a professor at the University of California, Berkeley and a pioneer in this area of chemistry, who was not involved in the study.
The research team, led by SLAC/Stanford professors Yi Cui and Wah Chiu, described the study today in the journal Matter.
Read more at DOE/SLAC National Accelerator Laboratory
Image: Cryo-EM images show a slice through a single MOF particle in atomic detail (left), revealing cage-like molecules (center) that can trap other molecules inside. The image at right shows carbon dioxide molecules trapped in one of the cages -- the first time this has ever been observed. Bottom right, a drawing of the molecular structure of the cage and the trapped CO2. (Credit: Li et al., Matter, 26 June 2019)