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ZIFs_surface_vs_confined_water_adsorption_reactivity_Momeni_et_al.pdf (6.32 MB)
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Stability of Zeolitic-imidazolate Frameworks in Humid Environments: Disentangling the Roles of Confined vs. Surface Water

preprint
submitted on 13.09.2020 and posted on 14.09.2020 by Mohammad R. Momeni, Farnaz A. Shakib
Most of the chemistry in nanoporous materials with small pore sizes and windows are known to occur on the surface of the material which is in immediate contact with substrate/solvent, rather than inside the pores and channels. Experimentally, it is not straightforward to distinguish the chemistry of confinement from the surface. Comprehensive molecular dynamics simulations coupled with quantum mechanical calculations are employed to decipher stability of zeolitic-imidazolate frameworks in aqueous solutions. Water adsorption properties are compared and contrasted in crystalline bulk vs. nanopoarticles of ZIF-8 as a representative of the ZIF family in order to fully disentangle how water interacts with the surface of the material which contains coordinatively unsaturated metal sites compared to the pristine bulk.
Our following detailed mechanistic study reveals the significantly higher propensity of the surface with coordinatively unsaturated Zn$^{2+}$ sites toward water attack and hydrolysis. Our results presented in this work are general and are applicable to other nanoporous materials with small particle sizes, pores and windows and are useful in devising plans for synthesis of more robust water stable materials for applications that involve atmospheric and/or bulk water.

History

Email Address of Submitting Author

mrmomenitaheri@gmail.com

Institution

New Jersey Institute of Technology

Country

United States

ORCID For Submitting Author

0000-0002-7731-5823

Declaration of Conflict of Interest

There are no conflicts to declare.

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