High-Capacity Gas Storage by a Microporous Oxalamide-Functionalized NbO-Type Metal–Organic Framework

A microporous oxalamide-functionalized NbO-type metal–organic framework, HNUST-3, has been designed and synthesized by self-assembling [Cu2(COO)4] paddlewheel SBUs and a novel tetracarboxylate ligand with linking oxalamide groups. HNUST-3 represents the first example of a porous oxalamide-functionalized MOF, which exhibits a high BET surface area of 2412 m2·g–1, large H2 uptake (unsaturated total capacity of 6.1 wt % at 20 bar and 77 K), and excellent CH4 storage (135.8 cm3(STP)­cm–3 at 20 bar and 298 K) as well as high CO2 adsorption capacity (20.2 mmol·g–1 at 20 bar and 298 K) with good selectivity for CO2 over CH4 (7.9) and N2 (26.1) at 298 K.