Precise Pore Engineering of a Pillar-Layered MOF via the Dual-Ligand Strategy for C2H2/CO2 Separation.

The efficient separation of acetylene (C2H2) and carbon dioxide (CO2) 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 C2H2/CO2. The coordination of different ligands generates 1D [Zn4N6]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 C2H2 adsorption capacity and excellent C2H2/CO2 separation ability. Furthermore, its relatively low C2H2 Qst, competitive thermal stability, and recyclability underscore its practicality for C2H2/CO2 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.