Bioinspired Design of a Giant [Mn86] Nanocage‐Based Metal‐Organic Framework with Specific CO2 Binding Pockets for Highly Selective CO2 Separation

• Published in: Angewandte Chemie International Edition 2023-08, Vol.62 (32), p.e202305390-n/a
• Main Authors: Geng, Shubo, Xu, Hang, Cao, Chun‐Shuai, Pham, Tony, Zhao, Bin, Zhang, Zhenjie
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Biomimetics; Carbon dioxide; Carbon dioxide removal; Dipole interactions; Energy security; Fabrication; Gas mixtures; Gas Separation; Gases; Metal-organic frameworks; Metal–Organic Framework; Methane; Physicochemical properties; Selectivity; Sorbents; Trap for CO2
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202305390

Adsorption‐based removal of carbon dioxide (CO2) from gas mixtures has demonstrated great potential for solving energy security and environmental sustainability challenges. However, due to similar physicochemical properties between CO2 and other gases as well as the co‐adsorption behavior, the selectivity of CO2 is severely limited in currently reported CO2‐selective sorbents. To address the challenge, we create a bioinspired design strategy and report a robust, microporous metal–organic framework (MOF) with unprecedented [Mn86] nanocages. Attributed to the existence of unique enzyme‐like confined pockets, strong coordination interactions and dipole‐dipole interactions are generated for CO2 molecules, resulting in only CO2 molecules fitting in the pocket while other gas molecules are prohibited. Thus, this MOF can selectively remove CO2 from various gas mixtures and show record‐high selectivities of CO2/CH4 and CO2/N2 mixtures. Highly efficient CO2/C2H2, CO2/CH4, and CO2/N2 separations are achieved, as verified by experimental breakthrough tests. This work paves a new avenue for the fabrication of adsorbents with high CO2 selectivity and provides important guidance for designing highly effective adsorbents for gas separation. Using a bioinspired design strategy, a CO2‐selective metal–organic framework (MOF), NKMOF‐9 a, is fabricated, which possesses unprecedented [Mn86] nanocage‐based structure and high structure robustness. Attributed to the unique enzyme‐like CO2‐binding pockets, NKMOF‐9 a can selectively remove CO2 from CO2/C2H2, CO2/CH4 and CO2/N2 mixtures with high selectivities.