An unprecedented water stable acylamide-functionalized metal–organic framework for highly efficient CH4/CO2 gas storage/separation and acid–base cooperative catalytic activity

Abstract

The high porosity, excellent water stability and optimized supramolecular host–guest interactions of MOFs are the three key factors for their potential practical applications in many important areas including gas storage/separation, catalysis and so on. In this study, we designed and constructed a highly porous (3, 36)-connected txt-type acylamide-functionalized metal–organic framework (HNUST-8) from a pyridine-based acylamide-linking diisophthalate and dicopper(II)-paddlewheel clusters. Interestingly, HNUST-8 possesses an exceptionally water-stable framework with a high BET surface area of about 2800 m² g⁻¹. At 298 K, HNUST-8 exhibits a high excess CO₂ uptake of 19.7 mmol g⁻¹ at 40 bar, an excellent total CH₄ storage capacity of 223 cm³(STP) cm⁻³ with a large working capacity of 178 cm³(STP) cm⁻³ at 80 bar, as well as highly efficient CO₂/CH₄ and CO₂/N₂ separation under dynamic conditions at 1 bar. Moreover, with the Lewis acidic open copper(II) sites and Lewis basic acylamide groups integrated into the framework, HNUST-8 demonstrates efficient catalytic activity as an acid–base cooperative catalyst in a tandem one-pot deacetalization–Knoevenagel condensation reaction.