High-Throughput Screening of MOF Adsorbents and Membranes for H₂ Purification and CO₂ Capture

Metal organic frameworks (MOFs) have emerged as great adsorbent and membrane candidates for separation of CO₂/H₂ mixtures. The main challenge is the existence of thousands of MOFs, which requires computational screening methods to identify the best materials prior to experimental efforts. In this study, we performed high-throughput computational screening of MOFs to examine their adsorbent and membrane performances for CO₂/H₂ separation. Grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were used to compute various adsorbent and membrane performance metrics of 3857 MOFs. CO₂/H₂ adsorption selectivities of MOFs at pressure swing adsorption (PSA) and vacuum swing adsorption (VSA) conditions were calculated to be in the range of 2.5-25 000 and 2.5-85 000, respectively, outperforming many zeolite adsorbents. Correlations between the ranking of MOF adsorbents at the PSA and VSA conditions were examined. H₂/CO₂ selectivities and H₂ permeabilities of MOF membranes were computed as 2.1 × 10^-5-6.3 and 230-1.7 × 10⁶ Barrer, respectively. A high number of MOF membranes was identified to surpass the upper bound defined for polymers due to high gas permeabilities of MOFs. Structure-performance relations revealed that MOFs with narrow pore sizes and low porosities are the best adsorbent materials for separation of CO₂ from H₂, whereas MOFs with large pore sizes and high porosities are the best membrane materials for selective separation of H₂. Our results will guide the selection of MOF adsorbents and membranes for efficient H₂ purification and CO₂ capture processes.