(293h) Design, Synthesis, and Characterization of Functionalized MOFs for Chemical Warfare Agent Capture
There is a pressing need for materials capable of rapidly detecting and destroying chemical warfare agents and other toxic chemicals. Stratified metal-organic frameworks (MOFs) containing plasmonic nanoparticles may be able to meet this need. Stratified MOFs consist of layered materials having different functional groups in each layer, the purpose of which is to provide a gradient of functional groups to direct transport of dilute target analytes to the center of the MOF, where an embedded plasmonic nanoparticle could serve to both detect the presence of the analyte through surface enhanced spectroscopy, and destroy it through plasmonic catalysis. We seek to develop a detailed understanding of the fundamental properties of sorption, transport, photodetection, and photocatalytic degradation of target chemical species in stratified hybrid MOF-nanoparticle systems. The first step to achieve this is to design, synthesize, and evaluate MOFs to identify promising functional groups to produce differential binding of analytes. We use quantum mechanical methods to identify functional groups for binding target species, Monte Carlo methods to perform fluid adsorption isotherms in candidate MOFs, and ab initio molecular dynamics to sample configurations and determine optimal binding sites in MOFs. In addition, we synthesize robust Zr and Hf-based MOFs with specific functional groups, measure isotherms of target molecules to compare with calculations, and use temperature programmed desorption to measure loading and binding energies of target molecules in MOFs. Further, we evaluate the stability of the MOFs in the presence of the target chemical species through use of the growing string method and mass spectrometry.