Electro-field alignment in a novel metal–organic framework for benchmark separation of ethylene from a ternary gas mixture

One-step separation of C₂H₄ from ternary gas mixtures containing acetylene (C₂H₂), ethylene (C₂H₄), and carbon dioxide (CO₂) represents a great challenge in chemical industry. Herein, we report the electro-field alignment in a novel anion-pillared MOF (SIFSIX-TEPE-Cu) for benchmark C₂H₄ separation from C₂H₂/CO₂/C₂H₄ gas mixtures. The semi-cage cavities featuring capped facets generated negative potentials along anion pillars and compensatory positive-charged electro-fields along organic ligands (TEPE) that facilitate specific recognitions of C₂H₂ and CO₂ over C₂H₄. As a result, SIFSIX-TEPE-Cu exhibits high adsorption capacities for C₂H₂ (123 cm³ g⁻¹) and CO₂ (65 cm³ g⁻¹) at 1.0 bar and 298 K. Notably, the record-high C₂H₂ uptake (78 cm³ g⁻¹) at 0.01 bar and remarkable C₂H₂/C₂H₄ selectivity (615.2) renders benchmark trace C₂H₂ removal ability. Dynamic breakthrough experiments demonstrate the benchmark productivity for high-purity C₂H₄ (>99.995%) of 194.7 mol kg⁻¹ and 5.96 mol kg⁻¹ from binary C₂H₂/C₂H₄ (1/99, v/v) and ternary C₂H₂/CO₂/C₂H₄ (1/9/90, v/v/v) gas mixtures.