(449cg) High-Throughput Screening of Metal-Organic Frameworks for CO2 Capture at High Humidity

One of the main challenges for the development of technology to capture CO₂ from power plant flue gas is to find or create materials with high selectivity for CO₂ at high humidity. Metal-organic frameworks (MOFs) have gained significant attention due to their excellent performance in gas adsorption and separation. However, water adsorption in MOFs is generally detrimental to CO₂ separation, and the removal of water content from flue gas prior to CO₂ capture would add to the overall cost. In this study, the CoRE (Computation-Ready, Experimental) MOF database of existing MOF structures has been computationally screened to find MOF candidates that are highly selective toward CO₂ over H₂O using a hierarchical computational screening approach. MOF candidates were selected based on the ratio of Henryâ??s constants of CO₂ over H₂O computed via Widom insertion method, corresponding to the selectivity of CO₂ over H₂O, and the adsorption isotherms of selected MOFs with high selectivities were assessed using more accurate partial charges from density function theory (DFT) calculations by grand canonical Monte Carlo (GCMC) simulation. Finally, the top MOF candidates with high CO₂/H₂O selectivity were identified. Decomposition of interaction energy between MOF and adsorbate show that the electrostatic interaction contributes to the majority of the adsorption energy of H2O in these selected MOFs. This work shows a path for the discovery of adsorbent materials for CO₂ capture at high humidity by large-scale computational screening.