Hydrogen bond unlocking-driven pore structure control for shifting multi-component gas separation function.

Purification of ethylene (CH) as the most extensive and output chemical, from complex multi-components is of great significance but highly challenging. Herein we demonstrate that precise pore structure tuning by controlling the network hydrogen bonds in two highly-related porous coordination networks can shift the efficient CH separation function from CH/CH/CH ternary mixture to CO/CH/CH/CH quaternary mixture system. Single-crystal X-ray diffraction revealed that the different amino groups on the triazolate ligands resulted in the change of the hydrogen bonding in the host network, which led to changes in the pore shape and pore chemistry. Gas adsorption isotherms, adsorption kinetics and gas-loaded crystal structure analysis indicated that the coordination network Zn-fa-atz (2) weakened the affinity for three C2 hydrocarbons synchronously including CH but enhanced the CO adsorption due to the optimized CO-host interaction and the faster CO diffusion, leading to effective CH production from the CO/CH/CH/CH mixture in one step based on the experimental and simulated breakthrough data. Moreover, it can be shaped into spherical pellets with maintained porosity and separation performance.