The Chemistry of Metal Organic Frameworks Captured by Liquid and Gas Phase in Situ TEM
Abstract
Use nanoscale analytical characterization to understand and quantify the post-synthetic modification (PSM) of MOFs to develop viable synthesis routes for obtaining complex, novel MOF nanostructures with tailored functionality. PSM of conventional MOF nanostructures has been widely reported for a variety of MOF systems and exchange species, both metal nodes and ligands, based on bulk-averaged and indirect characterization methods, such a PXRD, SEM-EDs, N2 sorption analysis, NMR, and ICP-MS/OES. However, MOF formation and the subsequent reactivity of the structural elements of MOFs has not been examined with nanoscale resolution and in individual crystal. High-resolution TEM imaging combined with STEM energy dispersive X-ray spectroscopy (EDS) elemental mapping provides a unique method for detailed structural and chemical analysis of these processes through direct characterization of single MOF crystals. Expected outcomes include a detailed understanding of the true extent of PME in individual MOF nanocrystals, and the pathways involved in such exchange processes. It is also possible we uncover alternative modification pathways, other than true exchange, which have not been previously considered. 2) Combine nanoscale experimental observation (in situ ETEM) with theoretical models of the absorption and sequestration of small molecules (breathing) in MOFs during environmental changes. Absorption of gases by MOFs is of great interest for the sequestration and remediation of gaseous toxins. However, these absorb/release processes in real MOFs, which are nanoscale crystals, is largely unknown. Previously under this grant, we have developed lattice models of MOF breathing, and here we seek to correlate our models with direct in situ characterization during breathing, using ETEM gas cycling and heat ramping while monitoring the transformation of individual MOF nanocrystals.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 06, 2018
- Accession Number
- AD1077126
Entities
People
- Francesco Paesani
- Nathan C. Gianneschi
- Seth M Cohen
Organizations
- Northwestern University
- University of California, San Diego