Low-Cost and High-Performance Microporous Metal–Organic Framework for Separation of Acetylene from Carbon Dioxide

Separation of acetylene (C₂H₂) from carbon dioxide (CO₂) is very difficult and challenging because of their similar molecular sizes and associated physical properties. Realization of low-cost and high-performance porous materials is of importance to facilitate the implementation of energy-efficient adsorptive separation into practical gas separation applications. Here, we utilized a cheap and commercially available formic acid ligand to successfully construct a robust MOF material [Ni₃(HCOO)₆·DMF] (1·DMF), offering high chemical stability, low cost, and high selectivity toward C₂H₂ over CO₂. The exceptional separation performance of the activated 1 is mainly attributed to the small pore size (4.3 Å) and functional O donor sites on the pore walls that provide strong binding affinity toward C₂H₂, as revealed by the detailed computational studies. This material thus exhibits ultrahigh low-pressure C₂H₂ uptake (38.2 cm³ cm^–3 at 0.01 bar and 298 K) and possesses a high C₂H₂/CO₂ selectivity (22.0 at ambient conditions), comparable to other leading porous materials. The high separation performance of 1 was further confirmed by the actual breakthrough experiments on a 50/50 C₂H₂/CO₂ mixture.