An ultramicroporous multi-walled metal–organic framework for efficient C 2 H 2 /CO 2 separation under humid conditions

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2023-11, Vol.11 (46), p.25605-25611
• Main Authors: Wang, Weize, Yuan, Wenke, Kong, Cunding, Yang, Yuchen, Xi, Shuting, Liu, Xiangyu, Liu, Bo
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D3TA05242G

The removal of carbon dioxide (CO 2 ) from acetylene (C 2 H 2 ) is not only industrially important for acetylene purification but also scientifically challenging owing to their high similarities in physical properties and molecular sizes. Multi-walled and ultramicroporous metal–organic frameworks (MOFs) can provide multiple specific interactions with C 2 H 2 supplied to form a cooperative effect for efficient separation properties. Herein, we report a new strategy involving the extension of vertices to create an infinite multi-walled MOF (In-TATB) from 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (H 3 TATB) and In( iii ) ions. Two 3D frameworks built from In( iii ) chains and TATB 3− molecules interpenetrate through strong π–π interactions between triazine rings. Taking advantage of the confined ultramicroporous space (3.8 Å × 4.1 Å) and accessible sites of multiple walls, In-TATB shows a high adsorption enthalpy of C 2 H 2 (36.6 kJ mol −1 at 298 K and low-coverage) and excellent separation of C 2 H 2 /CO 2 mixtures with an IAST selectivity of 11.8 (at 298 K and 1 bar). More importantly, both dry and wet breakthrough results validated its exceptional separation performance for C 2 H 2 /CO 2 mixtures, affording a high dynamic separation factor. This work provides a novel and powerful approach to address this extremely challenging gas separation in industry.