Reconfiguration of Electrostatic Interactions within an Ultramicroporous Metal–Organic Framework Enables CO₂ Separation

Developing highly efficient adsorbents for CO2 separation is significant in solving environmental challenges, but the trade-off between regenerability and selectivity undoubtedly limits their practical applications. Here, an ultramicroporous zinc metal–organic framework (Zn-MOF, termed as 1a) with decent CO2-affinity pore cavities is synthesized to enhance electrostatic interactions between CO2 and the pore surface for efficient CO2 purification from CO2/N2 and CO2/CH4 binary gas mixtures, in which the reconfiguration of electrostatic interactions within the 1a leads to a lower desorption temperature and high regenerability. Single-component gas adsorption isotherms indicate that 1a possesses a higher CO2 capacity of 33.7/62.1 cm3 g–1 (0.1/1 bar) at 298 K. Theoretical calculations suggest that the framework is electrostatically compatible with CO2 and can boost CO2 separation through multiple electrostatic interactions. Further, highly efficient separations of CO2/CH4 and CO2/N2 have been achieved and verified by column breakthrough tests.