Communications Chemistry (Jun 2023)

Mixed-linker strategy for suppressing structural flexibility of metal-organic framework membranes for gas separation

  • Chung-Kai Chang,
  • Ting-Rong Ko,
  • Tsai-Yu Lin,
  • Yen-Chun Lin,
  • Hyun Jung Yu,
  • Jong Suk Lee,
  • Yi-Pei Li,
  • Heng-Liang Wu,
  • Dun-Yen Kang

DOI
https://doi.org/10.1038/s42004-023-00917-2
Journal volume & issue
Vol. 6, no. 1
pp. 1 – 12

Abstract

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Abstract Structural flexibility is a critical issue that limits the application of metal-organic framework (MOF) membranes for gas separation. Herein we propose a mixed-linker approach to suppress the structural flexibility of the CAU-10-based (CAU = Christian-Albrechts-University) membranes. Specifically, pure CAU-10-PDC membranes display high separation performance but at the same time are highly unstable for the separation of CO2/CH4. A partial substitution (30 mol.%) of the linker PDC with BDC significantly improves its stability. Such an approach also allows for decreasing the aperture size of MOFs. The optimized CAU-10-PDC-H (70/30) membrane possesses a high separation performance for CO2/CH4 (separation factor of 74.2 and CO2 permeability of 1,111.1 Barrer under 2 bar of feed pressure at 35°C). A combination of in situ characterization with X-ray diffraction (XRD) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, as well as periodic density functional theory (DFT) calculations, unveils the origin of the mixed-linker approach to enhancing the structural stability of the mixed-linker CAU-10-based membranes during the gas permeation tests.