A High-Stability Co-MOF with Open Metal Sites for C2H2/CO2/CH4 Separation

One-step purification of C₂H₂ from ternary mixtures (C₂H₂, CO_2, and CH₄) can significantly reduce the energy consumption of the separation process, but it is extremely challenging. A new Co-MOF (TNU-BTTB-1) with a three-dimensional (3D) framework was synthesized, which displays high thermal stability, retaining its structural integrity at temperatures up to 400 °C. The structure possesses rich accessible open metal sites in the porous walls and shows high uptake for C₂H₂ (37.4 cm³ g^-1) and significant adsorption selectivity for C₂H₂ over CH₄ (20.1) and CO₂ (4.9) at 298 K and 100 kPa. Dynamic breakthrough studies show that it exhibits excellent C₂H₂ separation from C₂H₂/CO₂/CH₄ three-component mixtures.