Metal-Organic Framework with Rich Accessible Nitrogen Sites for Highly Efficient CO Capture and Separation.

A novel microporous metal-organic framework (FJU-44), with abundant accessible nitrogen sites on its internal surface, was constructed from the tetrapodal tetrazole ligand tetrakis(4-tetrazolylphenyl)ethylene (HTTPE) and copper chloride. Notably, the CO uptake capacity (83.4 cm/g, at 273 K and 1 bar) in the activated FJU-44a is higher than most of tetrazolate-containing MOF materials. Particularly, FJU-44a exhibits superior adsorption selectivity of CO/N (278-128) and CO/CH (44-16), which is comparable to some well-known CO capture materials. Furthermore, the fixed-bed breakthrough experiment indicates that the postcombustion flue gas flow over a packed column with FJU-44a adsorbents can be effectively separated.