Precise Pore Engineering of a Pillar-Layered MOF via the Dual-Ligand Strategy for C ₂ H ₂ /CO ₂ Separation

The efficient separation of acetylene (C 2 H 2 ) and carbon dioxide (CO 2 ) is of major practical importance but remains difficult because of their analogous physical properties. The dual-ligand strategy provides an effective approach to tailor pore structure and chemical microenvironments for enhanced functionality. Nevertheless, the structural controllability of metal–organic frameworks (MOFs) assembled from tetracarboxylic acids and azole ligands remains challenging. Herein, we report a unique pillar-layered MOF, Zn-TCPB-dmtrz, constructed based on a dual-ligand strategy, demonstrating the efficient separation of C 2 H 2 /CO 2 . The coordination of different ligands generates 1D [Zn 4 N 6 ] n chains, which function as pillars to interconnect 2D layers into a rare pillar-layered structure. The combination of abundant N/O sites and hydrophobic pore environment achieves high C 2 H 2 adsorption capacity and excellent C 2 H 2 /CO 2 separation ability. Furthermore, its relatively low C 2 H 2 Q st, competitive thermal stability, and recyclability underscore its practicality for C 2 H 2 /CO 2 separation. This study enriches the structural diversity of pillar-layered MOFs and demonstrates the controllable dual-ligand strategy based on tetracarboxylic acid and dmtrz ligands for advanced gas separation.