Highly cooperative CO2 adsorption via a cation crowding mechanism on a cesium-exchanged phillipsite zeolite

Hyun June Choi, Elliott L. Bruce, Kevin S. Kencana, Jingeon Hong, Paul A. Wright*, Suk Bong Hong*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)
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Abstract

An understanding of the CO2 adsorption mechanisms on small-pore zeolites is of practical importance in the development of more efficient adsorbents for the separation of CO2 from N2 or CH4. Here we report that the CO2 isotherms at 25–75 °C on cesium-exchanged phillipsite zeolite with a Si/Al ratio of 2.5 (Cs-PHI-2.5) are characterized by a rectilinear step shape: limited uptake at low CO2 pressure (PCO2) is followed by highly cooperative uptake at a critical pressure, above which adsorption rapidly approaches capacity (2.0 mmol g−1). Structural analysis reveals that this isotherm behavior is attributed to the high concentration and large size of Cs+ ions in dehydrated Cs-PHI-2.5. This results in Cs+ cation crowding and subsequent dispersal at a critical loading of CO2, which allows the PHI framework to relax to its wide pore form and enables its pores to fill with CO2 over a very narrow range of PCO2. Such a highly cooperative phenomenon has not been observed for other zeolites.
Original languageEnglish
Article numbere202305816
Number of pages9
JournalAngewandte Chemie International Edition
Volume62
Issue number36
Early online date30 Jun 2023
DOIs
Publication statusPublished - 4 Sept 2023

Keywords

  • Aluminosilicates
  • Carbon dioxide adsorption
  • Crowding mechanism
  • Structure elucidation
  • Zeolites

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