LAUSR

Two-dimensional metal-organic frameworks (MOFs) are promising candidates for high performance gas separation membranes. Currently, MOF nanosheets are mostly fabricated through delamination of layered MOFs, which often results in a low yield of intact free-standing nanosheets. In this work, we present a direct synthesis method for zinc(II)-benzimidazole-acetate (Zn(Bim)OAc) MOF nanosheets. The obtained nanosheets have a lateral dimension of 600 nm when synthesized at room temperature. By adjusting the synthesis temperature, the morphology of obtained nanosheets can be readily tuned from nanosheets to nanobelts. Using zeolite nanosheets of known thickness as internal standard, we introduce a method based on high-angle annular dark-field scanning transmission electron microscopy images to determine nanosheet thickness. The thickness of Zn(Bim)OAc nanosheets is determined to be 7 nm, which combined with their estimated pore opening makes them promising building blocks for gas separation membranes.