Abstract
An efficient carbon capture and release system necessitates rapid CO2 transport to and from active sites, a property typically associated with permanently porous materials featuring large surface areas. Here, we present hydrophobic organic crystals of alkylated monoethanolamine that, despite their nonporous nature, undergo a rapid and reversible solid-to-solid phase transition upon CO₂ uptake and release. Exposure to CO2 triggers a thermodynamically favored structural rearrangement, enabling quantitative CO2 capture and forming a stable carbamate, aided by intermolecular interactions involving the long side chains. This process is fully reversible under practical flue-gas CO2 capture conditions (>0.6% CO2, 0−100% relative humidity) and enables low-temperature desorption using CO2 itself as a stripping gas (65 °C at 1 atm CO2). Structural analysis through in situ XRPD, solid-state NMR spectroscopy, electron diffraction, and Raman analysis confirms that these hydrophobic absorbents selectively uptake CO2 to form an anhydrous ammonium carbamate pair in the solid state. The non-hygroscopic nature of these organic crystals is exemplified by a representative C10-MEA in the presence of CO2, resulting in a desorption process with a minimal temperature swing (ΔTabs-des = 30 °C), offering an energy-efficient (>1.2 GJ/t of captured CO₂) and economically viable alternative for carbon capture applications.
Data availability
All data is available in the Supplementary Information and from the corresponding authors on request. Correspondence and requests for materials should be addressed to J.-W.L. The supplementary crystallographic data for this paper is included in the Supplementary Information. This data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/structures.
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Acknowledgements
The generous support from the Department of Chemistry, University of Copenhagen, Villum Fonden (00019062, J.-W.L.), Independent Research Fund Denmark (DFF-Research Project1, Thematic Research, 0217-00192B, J.-W.L.), Carlsberg Fonden (CF21-0308, J.-W.L., 2013_01_0589, CF14-0230, CF20-0130, H. N. B), NNF Pioneer Innovator Grant (NNF 0095061, J.-W.L.), NNF NERD (NNF22OC0076002, N. C. N.) and the NNF CO2 Research Center (CORC, NNF21SA0072700, K.D., J.-W.L.) is gratefully acknowledged. The authors acknowledge the MAX IV Laboratory for beamtime on the BioMAX beamline under proposal 20241845 and on the DanMAX beamline under proposal 20230769. Research conducted at MAX IV, a Swedish national user facility, is supported by Vetenskapsrådet (Swedish Research Council, VR) under contract 2018-07152, Vinnova (Swedish Governmental Agency for Innovation Systems) under contract 2018-04969, and Formas under contract 2019-02496. DanMAX is funded by the NUFI grant no. 4059-00009B. In addition, the authors gratefully acknowledge A. Gonzales, E. Panepucci, L. Krause, K. Christensen, M. R. Jørgensen, and I. Kantor from the MAX IV Laboratory for assistance with the XRD experiments and data conversion. Electron diffraction experiments are supported by the Novo Nordisk Foundation Research Infrastructure grant NNF220C0074439. A.L. thanks D.N. Rainer, J.P. Tidey, and C. Wilson for the fruitful discussions about 3D ED experiments and data analysis. The authors acknowledge the use of instrumentation at the Danish Center for Ultrahigh-Field NMR Spectroscopy, funded by the Danish Ministry of Higher Education and Science (AU-2010-612-181) and Novo Nordisk Foundation Research Infrastructure − Large Equipment and Facilities program (NNF220C0075797). The authors gratefully acknowledge K. Qvortrup for performing the SEM analysis and T. M. Nielsen for assistance with the synchrotron setup. Further, the authors acknowledge T. Runčevski and I. Čorić for the insightful discussions regarding the crystal structures. The authors also thank their analytical departments, the CORC, and its NCCC theme members for helpful discussions.
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Author contributions: J.-W.L. R.J.S.L and A.P. designed the project. A.P., R.J.S.L., A.L., K.A., G.B.H, N.C.N., A.A.A., K.L.L.O., H.N.B., K.D., and D.W.J. performed the experiments and analyzed the data. A.P. and J.-W.L. wrote the first draft of the manuscript. All authors provided feedback, proofreading, and oversaw the experiments and data analysis.
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J.-W.L., R.J.S.L., and A.P., as the inventors, declare competing interests with a preliminary patent application from the University of Copenhagen to the Danish Patent Office (EP24196465.9, filed), regarding the use of Cn-MEA in CO2 capture and release. J.-W.L., R.J.S.L., and A.P. declare no other competing interests. The remaining authors declare no competing interests.
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Petrović, A., Lima, R.J.d.S., Hadaf, G.B. et al. Nonporous hydrophobic organic crystals for carbon dioxide capture via chain-melting phase transition. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69006-x
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DOI: https://doi.org/10.1038/s41467-026-69006-x
