Temperature-dependent rearrangement of gas molecules in ultramicroporous materials for tunable adsorption of CO<sub>2</sub> and C<sub>2</sub>H<sub>2</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37355678.
- Also identified by DOI 10.1038/s41467-023-39319-2 and PMC identifier 10290667.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The interactions between adsorbed gas molecules within porous metal-organic frameworks are crucial to gas selectivity but remain poorly explored. Here, we report the modulation of packing geometries of CO<sub>2</sub> and C<sub>2</sub>H<sub>2</sub> clusters within the ultramicroporous CUK-1 material as a function of temperature. In-situ synchrotron X-ray diffraction reveals a unique temperature-dependent reversal of CO<sub>2</sub> and C<sub>2</sub>H<sub>2</sub> adsorption affinities on CUK-1, which is validated by gas sorption and dynamic breakthrough experiments, affording high-purity C<sub>2</sub>H<sub>2</sub> (99.95%) from the equimolar mixture of C<sub>2</sub>H<sub>2</sub>/CO<sub>2</sub> via a one-step purification process. At low temperatures (<253 K), CUK-1 preferentially adsorbs CO<sub>2</sub> with both high selectivity (>10) and capacity (170 cm<sup>3</sup> g<sup>-1</sup>) owing to the formation of CO<sub>2</sub> tetramers that simultaneously maximize the guest-guest and host-guest interactions. At room temperature, conventionally selective adsorption of C<sub>2</sub>H<sub>2</sub> is observed. The selectivity reversal, structural robustness, and facile regeneration of CUK-1 suggest its potential for producing high-purity C<sub>2</sub>H<sub>2</sub> by temperature-swing sorption.
Medical subject headings
- Carbon Dioxide
- Cold Temperature