An Azine-Linked Covalent Organic Framework: Synthesis, Characterization and Efficient Gas Storage

A azine-linked covalent organic framework, COF-JLU2, was designed and synthesized by condensation of hydrazine hydrate and 1,3,5-triformylphloroglucinol under solvothermal conditions for the first time. The new covalent organic framework material combines permanent micropores, high crystallinity, good thermal and chemical stability, and abundant heteroatom activated sites in the skeleton. COF-JLU2 possesses a moderate BET surface area of over 410 m² g^-1 with a pore volume of 0.56 cm³ g^-1. Specifically, COF-JLU2 displays remarkable carbon dioxide uptake (up to 217 mg g^-1) and methane uptake (38 mg g^-1) at 273 K and 1 bar, as well as high CO₂/N₂ (77) selectivity. Furthermore, we further highlight that it exhibits a higher hydrogen storage capacity (16 mg g^-1) than those of reported COFs at 77 K and 1 bar.