High CO2 separation performance on a metal–organic framework composed of nano-cages lined with an ultra-high density of dual-side open metal sites

Abstract

Developing efficient adsorbents for CO₂ separation is the crucial step of CO₂ sequestration. which has found many applications, including in carbon capture from flue gas and natural gas purification. Although many adsorbents have been reported in the past few decades, developing efficient adsorbents with high separation selectivity and excellent capacity is technically challenging due to the trade-off effect between the adsorption capacity and selectivity. This work reports the CO₂ separation performance of a microporous MOF, which comprises nano-cages and an ultra-high density of dual-side open metal sites. The adsorption results reveal a prominent CO₂ uptake and outstanding separation selectivity for CO₂/N₂ and CO₂/CH₄. Furthermore, this MOF also exhibits the preferable adsorption of C2–C3 light hydrocarbons over CH₄. Simulation studies reveal that the dual-side open metal sites are the preferable adsorption sites for CO₂, C₂H₄, and C₃H₆. Therefore, the outstanding separation performance can be attributed to the combined effects of nano-cages and the high density of open metal sites.