| Autor: |
Ahmad M; Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794-0701, United States.; Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States., Patel R; Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States.; Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, United States., Lee DT; Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794-0701, United States.; Department of Chemical and Biomolecular Engineering & Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland 21218-2625, United States., Corkery P; Department of Chemical and Biomolecular Engineering & Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland 21218-2625, United States., Kraetz A; Department of Chemical and Biomolecular Engineering & Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland 21218-2625, United States., Prerna; Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States.; Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, United States., Tenney SA; Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States., Nykypanchuk D; Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States., Tong X; Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States., Siepmann JI; Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, United States.; Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, United States., Tsapatsis M; Department of Chemical and Biomolecular Engineering & Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, Maryland 21218-2625, United States.; Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland 20723, United States., Boscoboinik JA; Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794-0701, United States.; Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States. |
| Abstrakt: |
Zeolitic imidazolate framework (ZIF-8) is a promising material for gas separation applications. It also serves as a prototype for numerous ZIFs, including amorphous ones, with a broader range of possible applications, including sensors, catalysis, and lithography. It consists of zinc coordinated with 2-methylimidazolate (2mIm) and has been synthesized with methods ranging from liquid-phase to solvent-free synthesis, which aim to control its crystal size and shape, film thickness and microstructure, and incorporation into nanocomposites. Depending on the synthesis method and postsynthesis treatments, ZIF-8 materials may deviate from the nominal defect-free ZIF-8 crystal structure due to defects like missing 2mIm, missing zinc, and physically adsorbed 2mIm trapped in the ZIF-8 pores, which may alter its performance and stability. Infrared (IR) spectroscopy has been used to assess the presence of defects in ZIF-8 and related materials. However, conflicting interpretations by various authors persist in the literature. Here, we systematically investigate ZIF-8 vibrational spectra by combining experimental IR spectroscopy and first-principles molecular dynamics simulations, focusing on assigning peaks and elucidating the spectroscopic signals of putative defects present in the ZIF-8 material. We attempt to resolve conflicting assignments from the literature and to provide a comprehensive understanding of the vibrational spectra of ZIF-8 and its defect-induced variations, aiming toward more precise quality control and design of ZIF-8-based materials for emerging applications. |
