Untwisted restacking of two-dimensional metal-organic framework nanosheets for highly selective isomer separations
Tao, ZR (Tao, Ze-Rong)[ 1 ] ; Wu, JX (Wu, Jian-Xiang)[ 1 ] ; Zhao, YJ (Zhao, Ying-Jie)[ 2 ] ; Xu, M (Xu, Ming)[ 1 ] ; Tang, WQ (Tang, Wen-Qi)[ 1 ] ; Zhang, QH (Zhang, Qing-Hua)[ 3 ] ; Gu, L (Gu, Lin)[ 3 ] ; Liu, DH (Liu, Da-Huan)[ 2 ] ; Gu, ZY (Gu, Zhi-Yuan)[ 1 ] *（古志远）
[ 1 ] Nanjing Normal Univ, Jiangsu Collaborat Innovat Ctr Biomed Funct Mat, Coll Chem & Mat Sci, Jiangsu Key Lab Biofunct Mat, Nanjing 210023, Jiangsu, Peoples R China
[ 2 ] Beijing Univ Chem Technol, Beijing Adv Innovat Ctr Soft Matter Sci & Engn, State Key Lab Organ Inorgan Composites, Beijing 100029, Peoples R China
[ 3 ] Chinese Acad Sci, Inst Phys, Beijing 100190, Peoples R China
The stacking between nanosheets is an intriguing and inevitable phenomenon in the chemistry of nano-interfaces. Two-dimensional metal-organic framework nanosheets are an emerging type of nanosheets with ultrathin and porous features, which have high potential in separation applications. Here, the stacking between single-layer metal-organic framework nanosheets is revealed to show three representative conformations with tilted angles of 8 degrees, 14 degrees, and 30 degrees for Zr-1, 3, 5-(4-carboxylphenyl)-benzene framework as an example. Efficient untwisted stacking strategy by simple heating is proposed. A detailed structural analysis of stacking modes reveals the creation of highly ordered sub-nanometer micropores in the interspacing of untwisted nano-layers, yielding a high-resolution separator for the pair of para-/meta-isomers over the twisted counterparts and commercial HP-5MS and VF-WAXMS columns. This general method is proven by additional nanosheet examples and supported by Grand Canonical Monte Carlo simulation. This finding will provide a synthetic route in the rational design of functionalities in two-dimensional metal-organic framework nanosheet.