Two dimensional Ti-based metal-organic framework with polar oxygen atoms on the pore surface for efficient gas separation

The separation of gas molecules with similar diameters and shapes is an important area of research. Herein, we carefully studied a Ti-based metal-organic framework (NTU-9). The six coordination sites of each Ti4+ atom in this MOF are evenly distributed by three dobdc(4-) to form a two-dimensional (2-D) layered structure. Uncoordinated carboxyl O atoms between layers create a robust 3D framework by forming hydrogen bonds. The Brunauer-Emmett-Teller (BET) surface area of NTU-9 at 77 K is 917 m(2) g(-1). Benefit from the polar oxygen atoms vast in the surface of the one-dimensional (1-D) channel, NTU-9 shows a C2H2 adsorption capacity of 118 cm(3) g(-1) and a C2H2/CO2 selectivity of 3.5 under ambient conditions and has a moderate heat of adsorption for C2H2 (30 kJ mol(-1)). These findings may provide alternative strategies for gas separation. (C) 2020 Elsevier Ltd. All rights reserved.