Achieving high-performance acetylene/carbon dioxide separation via green and scalable synthesis of high-density...

A high-density Co-based metal-organic framework (3D-PL-MOF) was successfully synthesized, featuring a heptanuclear cobalt cluster for highly efficient C₂H₂/CO₂ separation. The material exhibits exceptional stability and significant gas uptake, achieving adsorption capacities of 66.3 cm³ g^-1 for C₂H₂ and 49.7 cm³ g^-1 for CO₂ at 298 K and 1 bar. Critically, the C₂H₂ uptake markedly exceeds that of CO₂ in the low-pressure region. Molecular simulations and calculated isosteric heats of adsorption reveal that the framework's interaction forces with C₂H₂ are significantly stronger than those with CO₂. The 3D-PL-MOF demonstrates outstanding separation performance, enabling the recovery of high-purity C₂H₂ from an equimolar C₂H₂/CO₂ mixture with a yield of 51.4 L kg^-1. The stability of the material has been demonstrated through breakthrough tests under both three consecutive cycles and 50 % relative humidity conditions. Importantly, the 3D-PL-MOF is amenable to low-cost, gram-scale synthesis utilizing a simple, green water/ethanol solvent system. This work not only introduces a promising material for energy-efficient gas separation but also offers new strategies for developing adsorption separation materials that effectively combine high density with environmentally friendly synthesis.