Finely Tuned Framework Isomers for Highly Efficient C₂H₂ and CO₂ Separation

Obtaining the optimal physiadsorbents based on the same starting materials is one of the crucial technologies that can address the increasing problem of energy-consuming separation. Herein, a group of porous coordination isomers (NTU-51 to NTU-54) with topologies of sql, dia, nbo, and kgm has been newly designed and prepared from a 4-c square node (paddlewheel cluster) and a 2-c linker (isophthalic acid derivative). Pure gas measurements revealed that they have a varied ability for selective C₂H₂ capture from C₂H₂/CO₂ mixtures, originating from the fine arrangement of functional sites within these isomers as well as size-exclusive effects. Further dynamic breakthrough experiments exhibited good C₂H₂/CO₂ (1/1, v/v) separation performance of the two isomers (NTU-53 and NTU-54) in both dry and humid gas phases (R.H. = 45%). More interestingly, stability tests and long-term measurements demonstrated a high potential of them to be used under realistic conditions.