The impact of crystal size and temperature on the adsorption-induced flexibility of the Zr-based metal-organic framework DUT-98

  1. Simon KrauseORCID Logo,
  2. Volodymyr BonORCID Logo,
  3. Hongchu DuORCID Logo,
  4. Rafal E. Dunin-BorkowskiORCID Logo,
  5. Ulrich Stoeck,
  6. Irena SenkovskaORCID Logo and
  7. Stefan Kaskel

Submitting author affiliation: University of Groningen, Groningen, Netherlands

Beilstein Arch. 2019, 201952. doi:10.3762/bxiv.2019.52.v1

Published 28 Jun 2019

  • Preprint

Abstract

In this contribution we analyse the influence of adsorption cycling, crystal size, and temperature on the switching behaviour of the flexible Zr-based metal-organic framework DUT-98. We observe a shift in the gate opening pressure upon cycling of adsorption experiments of micro meter-sized crystals and assign this to a fragmentation of the crystals. In a series of modulated syntheses we downsize the average crystal size of DUT-98 crystals from 120 µm to 50 nm and characterize the obtained solids by X-ray diffraction, infrared spectroscopy, as well as scanning and transmission electron microscopy. We analyse the adsorption behaviour by nitrogen and water adsorption at 77 K and 298 K, respectively and show that adsorption-induced flexibility is only observed for micro meter-sized crystals. Nanometer-sized crystals were found to exhibit reversible type I adsorption behaviour upon adsorption of nitrogen and exhibit a crystal-size dependent steep water uptake of up to 20 mmol g-1 at 0.5 p/p0 with potential for water harvesting and heat pump applications. We furthermore investigate the temperature-induced structural transition by in situ PXRD. At temperatures beyond 110 °C the open pore state of nano meter-sized DUT-98 crystals are found to irreversibly transform in a closed pore state. The connection of crystal fragmentation upon adsorption cycling and the crystal size-dependence of the adsorption-induced flexibility is an important finding for evaluation of these materials in future adsorption-based applications. This work thus extends the limited amount of studies on crystal size effects in flexible MOFs and hopefully motivates further investigations into this field.

Keywords: crystal engineering, flexible metal-organic frameworks, water adsorption, crystal size

Supporting Information

Format: PDF Size: 2.0 MB Download

How to Cite

When a peer-reviewed version of this preprint is available in the Beilstein Journals, this information will be updated in the information box above. If no peer-reviewed version is available, please cite this preprint using the following information:

Krause, S.; Bon, V.; Du, H.; Dunin-Borkowski, R. E.; Stoeck, U.; Senkovska, I.; Kaskel, S. Beilstein Arch. 2019, 201952. doi:10.3762/bxiv.2019.52.v1

Download Citation
Download RIS (Reference Manager) Download BIB (BIBTEX)

© 2019 Krause et al.; licensee Beilstein-Institut.
This is an Open Access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0). Please note that the reuse, redistribution and reproduction in particular requires that the authors and source are credited.
The license is subject to the Beilstein Archives terms and conditions: (https://www.beilstein-archives.org/xiv/terms)

Other Beilstein-Institut Open Science Activities

Logo
Logo
Logo
Symposia