Humidity-induced CO2 capture enhancement in Mg-CUK-1

Abstract

Kinetic CO₂ adsorption measurements in the water-stable and permanently microporous Metal–organic framework material, Mg-CUK-1, reveal a 1.8-fold increase in CO₂ capture from 4.6 wt% to 8.5 wt% in the presence of 18% relative humidity. Thermodynamic CO₂ uptake experiments corroborate this enhancement effect, while grand canonical Monte Carlo simulations also support the phenomenon of a humidity-induced increase in the CO₂ sorption capacity in Mg-CUK-1. Molecular simulations were implemented to gain insight into the microscopic adsorption mechanism responsible for the observed CO₂ sorption enhancement. These simulations indicate that the cause of increasing CO₂ adsorption enthalpy in the presence of H₂O is due to favorable intermolecular interactions between the co-adsorbates confined within the micropores of Mg-CUK-1.