Dense Packing of Acetylene in a Stable and Low-Cost Metal-Organic Framework for Efficient C₂ H₂ /CO₂ Separation

Porous materials for C₂ H₂ /CO₂ separation mostly suffer from high regeneration energy, poor stability, or high cost that largely dampen their industrial implementation. A desired adsorbent should have an optimal balance between excellent separation performance, high stability, and low cost. We herein report a stable, low-cost, and easily scaled-up aluminum MOF (CAU-10-H) for highly efficient C₂ H₂ /CO₂ separation. The suitable pore confinement in CAU-10-H can not only provide multipoint binding interactions with C₂ H₂ but also enable the dense packing of C₂ H₂ inside the pores. This material exhibits one of the highest C₂ H₂ storage densities of 392 g L^-1 and highly selective adsorption of C₂ H₂ over CO₂ at ambient conditions, achieved by a low C₂ H₂ adsorption enthalpy (27 kJ mol^-1 ). Breakthrough experiments confirm its exceptional separation performance for C₂ H₂ /CO₂ mixtures, affording both large C₂ H₂ uptake of 3.3 mmol g^-1 and high separation factor of 3.4. CAU-10-H achieves the benchmark balance between separation performance, stability, and cost for C₂ H₂ /CO₂ separation.