Nonporous hydrophobic organic crystals for carbon dioxide capture via chain-melting phase transition.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41634002.
- Also identified by DOI 10.1038/s41467-026-69006-x and PMC identifier 12976360.
- Licence recorded as CC BY-NC-ND.
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Abstract
An efficient carbon capture and release system necessitates rapid CO<sub>2</sub> 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 CO<sub>2</sub> triggers a thermodynamically favored structural rearrangement, enabling quantitative CO<sub>2</sub> capture and forming a stable carbamate, aided by intermolecular interactions involving the long side chains. This process is fully reversible under practical flue-gas CO<sub>2</sub> capture conditions (>0.6% CO<sub>2</sub>, 0-100% relative humidity) and enables low-temperature desorption using CO<sub>2</sub> itself as a stripping gas (65 °C at 1 atm CO<sub>2</sub>). Structural analysis through in situ XRPD, solid-state NMR spectroscopy, electron diffraction, and Raman analysis confirms that these hydrophobic absorbents selectively uptake CO<sub>2</sub> 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 CO<sub>2,</sub> resulting in a desorption process with a minimal temperature swing (ΔT<sub>abs-des</sub> = 30 °C), offering an energy-efficient (>1.2 GJ/t of captured CO₂) and economically viable alternative for carbon capture applications.