Nanosheets of a Layered Metal-Organic Framework for Separation of CO 2 /CH 4 using Mixed Matrix Membranes.

Mixed matrix membranes represent an important technology for gas separations. Nanosheets of metal-organic framework (MOF) materials of high aspect ratio and size-selective gas transport properties have the potential to promote the efficient mixing of components to form membranes for gas separation. Herein, we report a bottom-up synthesis of extended sheets of kagomé (kgm) topology, kgm ^{t -Bu} , via the linkage of [Cu ₂ (O ₂ CR) ₄ ] paddlewheels with 5- tert -butylisophthalic acid. The growth of the layered structure can be controlled by the choice of solvent and modulator. Nanosheets of kgm ^{t -Bu} of average thickness of 20 nm and aspect ratio of 40 to 50 can be obtained, and the sieving effect of the channels in kgm ^{t -Bu} boost the efficient separation of CO ₂ over CH ₄ . A mixed matrix membrane comprising kgm ^{t -Bu} nanosheets with Matrimid shows a 32% enhancement in CO ₂ /CH ₄ selectivity compared with the membrane incorporating the MOF in the particulate form.