Enhanced Carbon Dioxide Capture from Diluted Streams with Functionalized Metal−Organic Frameworks Gładysiak, Andrzej Song, Ah-Young Vismara, Rebecca Waite, Madison M. Alghoraibi, Nawal H. Alahmed, Ammar Younes, Mourad Huang, Hongliang A. Reimer, Jeffrey C. Stylianou, Kyriakos pore functionalization CO2 capture H2O isotherms Capturing carbon dioxide from diluted streams, such as flue gas originating from natural gas combustion, can be achieved using recyclable, humidity-resistant porous materials. Three such materials were synthesized by chemically modifying the pores of metal−organic frameworks (MOFs) with Lewis basic functional groups. These materials included aluminum 1,2,4,5- tetrakis(4-carboxylatophenyl) benzene (Al-TCPB) and two novel MOFs: Al-TCPB(OH), and Al-TCPB(NH2), both isostructural to Al-TCPB, and chemically and thermally stable. Single-component adsorption isotherms revealed significantly increased CO2 uptakes upon pore functionalization. Breakthrough experiments using a 4/96 CO2/N2 gas mixture humidified up to 75% RH at 25 °C showed that Al-TCPB(OH) displayed the highest CO2 dynamic breakthrough capacity (0.52 mmol/g) followed by that of Al- TCPB(NH2) (0.47 mmol/g) and Al-TCPB (0.26 mmol/g). All three materials demonstrated excellent recyclability over eight humid breakthrough-regeneration cycles. Solid-state nuclear magnetic resonance spectra revealed that upon CO2/H2O loading, H2O molecules do not interfere with CO2 physisorption and are localized near the Al-O(H) chain and the −NH2 functional group, whereas CO2 molecules are spatially confined in Al-TCPB(OH) and relatively mobile in Al-TCPB(NH2). Density functional theory calculations confirmed the impact of the adsorbaphore site between of two parallel ligand-forming benzene rings for CO2 capture. Our study elucidates how pore functionalization influences the fundamental adsorption properties of MOFs, underscoring their practical potential as porous sorbent materials. 2024-11-28T07:31:02Z 2024-11-28T07:31:02Z 2024-11-11 journal article Gładysiak, A. et. al. JACS Au 2024, 4, 4527−4536. [https://doi.org/10.1021/jacsau.4c00923] https://hdl.handle.net/10481/97480 10.1021/jacsau.4c00923 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional ACS Publications