The Chemistry of Metal Organic Frameworks Captured by Liquid and Gas Phase in Situ TEM
Technical Report,01 Jul 2015,30 Jun 2018
University of California - San Diego La Jolla United States
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Metal-organic frameworks MOFs are self-assembled networks of inorganic nodes metal ions or metal ion clusters often referred to as secondary building units, SBUs bridged by multitopic organic ligands i.e. linkers. MOFs are highly porous materials and are highly tunable by pre- or post-synthetic methods. MOFs have attracted great attention as materials for gas storage, separation, catalysis, and other uses. To date, there have been few studies on MOF formation, partly due to difficulties in analyzing the formation of the particles as they assemble and precipitate from solution, leaving a large gap in the understanding of mechanisms underlying the formation of these important materials such as how to precisely control and tune the porosity or final morphology. It is of course, precisely these properties of the materials that make them important and interesting. Furthermore, as MOF defects and nanoscale morphologies have been shown to be important for bulk properties, having a method to both analyze MOF formation and defects would be highly desirable in optimizing their synthesis or post-synthetic modification. Here we propose that scanning transmission electron microscopy STEM, both analytical and in situ environmental gas-phase andor heating can be used to observe the precise nanoscale structure of MOFs after synthesis or modification lattice-structure, morphology and elemental composition, and during complex functional processes such as the absorption and release of small molecules. Such studies will give unparalleled information about the fundamental mechanisms of formation, and the behavior of individual particles, information that can be used toward the development of specifically optimized functional MOFs.
- Test Facilities, Equipment and Methods
- Properties of Metals and Alloys