Abstract
The preferential identification of inert ethane molecules and the corresponding pore-filling mechanism are fundamentally challenging. Although flexible metal–organic frameworks are considered promising candidates to enhance ethane selectivity, their gate-opening pressures for ethane and ethylene are usually similar, which limits further improvement in their separation performance. Here, we report a flexible–robust metal–organic framework, TYUT-18, whose binary pore system combined with the flexible deformation of the framework produces significantly different gate-opening pressures for ethane (0.18 bar) and ethylene (0.48 bar) at 298 K, effectively reducing competitive adsorption in the same pore and improving overall separation efficiency, and achieves the purification of ultra-high purity ethylene (99.995%) with a separation productivity of 15.7 L kg−1. More importantly, we have systematically elucidated the dynamic filling behavior of ethane molecules in the flexible–robust framework system, a process of preferentially occupying the large pore cavities then filling into the small ones was uncovered using a combination of extensive single-crystal X-ray diffraction studies and density functional theory calculations. The evolution of this sequential guest-filling mechanism demonstrated the merit of binary pore networks for challenging gas separation tasks and thereby offers valuable insights for the design of highly selective separation materials.
Data availability
The data generated in this study are provided in the Supplementary Information/Source Data file. The X-ray crystallographic coordinate for structures reported in this article have been deposited at the CCDC under deposition numbers CCDC 2407210 (TYUT-18 (α)), 2412958 (TYUT-18 (β)), 2449695 (TYUT-18(β)•0.25C2H6), 2449696 (TYUT-18(α)•1C2H6), 2473904 (TYUT-18(α)•3C2H6), 2449694 (TYUT-18(α)•0.25C2H4). These data can be obtained free of charge from the CCDC via https://www.ccdc.cam.ac.uk/data_request/cif. Source data are provided with this paper. All data are available in the main text or the supplementary information. Source data are provided with this paper.
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Acknowledgements
The research work was supported by the National Key R&D Program of China (No. 2022YFB3806800 to L.L.), the National Natural Science Foundation of China (No. 22422810 to Y.C., 22278287 to L.L. and 22090062 to J.L.), and the Fundamental Research Program of Shanxi Province (No. 202203021223004 to L.L.).
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L.Z. was responsible for experimental design, sample synthesis, performance characterization, data processing and figure drawing and completed the paper writing. S.L. and W.Z. provided in-situ SCXRD testing support. Y.R. and Z.W. provided drawing and basic experimental support. Y.W. performed the DFT calculations. Y.C., Y.-B.Z., and L.-B.S. provided writing guidance. L.L. and J.L. conceived the idea and supervised the project. All authors contributed to the scientific discussion.
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Zhang, L., Liu, S., Zuo, W. et al. Sequential ethane filling induced structural transitions in a flexible–robust metal–organic framework for ethylene purification. Nat Commun (2026). https://doi.org/10.1038/s41467-026-71550-5
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DOI: https://doi.org/10.1038/s41467-026-71550-5
