Bioinspired Design of a Giant [Mn 86 ] Nanocage-Based Metal-Organic Framework with Specific CO 2 Binding Pockets for Highly Selective CO 2 Separation.

Adsorption-based removal of carbon dioxide (CO ₂ ) from gas mixtures has demonstrated great potential for solving energy security and environmental sustainability challenges. However, due to similar physicochemical properties between CO ₂ and other gases as well as the co-adsorption behavior, the selectivity of CO ₂ is severely limited in currently reported CO ₂ -selective sorbents. To address the challenge, we create a bioinspired design strategy and report a robust, microporous metal-organic framework (MOF) with unprecedented [Mn ₈₆ ] nanocages. Attributed to the existence of unique enzyme-like confined pockets, strong coordination interactions and dipole-dipole interactions are generated for CO ₂ molecules, resulting in only CO ₂ molecules fitting in the pocket while other gas molecules are prohibited. Thus, this MOF can selectively remove CO ₂ from various gas mixtures and show record-high selectivities of CO ₂ /CH ₄ and CO ₂ /N ₂ mixtures. Highly efficient CO ₂ /C ₂ H ₂ , CO ₂ /CH ₄ , and CO ₂ /N ₂ separations are achieved, as verified by experimental breakthrough tests. This work paves a new avenue for the fabrication of adsorbents with high CO ₂ selectivity and provides important guidance for designing highly effective adsorbents for gas separation.
(© 2023 Wiley-VCH GmbH.)