Target Synthesis of an Azo (N=N) Based Covalent Organic Framework with High CO2-over-N2 Selectivity and Benign Gas Storage Capability

An azo (N=N) based covalent organic framework (COF-TpAzo) has been synthesized via a Schiff base condensation reaction. The Braunauer-Emmett Teller (BET) specific surface area up to 1552 m(2).g(-1) was obtained for the framework with a pore volume of 0.97 cm(3).g(-1). The COF-TpAzo exhibits a high selectivity in CO2/N-2 (127/145 at 273/298 K, respectively, Henry method) due to the N-2-phobic and CO2-philic feature of COF-TpAzo. Furthermore, hydrogen and methane storage capacities of the nitrogen-rich COF-TpAzo have been investigated. The COF-TpAzo shows high H-2 and CH4 storage capacity at 1 bar (10.6 mg.g(-1) at 77 K for H-2, 11.2 mg.g(-1) at 273 K for CH4, and 5.5 mg.g(-1) at 298 K for CH4).