Hard-and-Soft Integration Strategy for Preparation of Exceptionally Stable Zr(Hf)-UiO-66 via Thiol–Ene Click Chemistry
mediaposted on 16.06.2020, 11:39 by Jingcheng Du, Li Chen, Xinjuan Zeng, Shuai Yu, Wei Zhou, Luxi Tan, Lichun Dong, Cailong Zhou, Jiang Cheng
UiO-66 metal–organic frameworks (MOFs) are unstable in some harsh aqueous environments, which limit their practical applications. We demonstrate a postsynthetic modification methodology to transform hydrophilic Zr(Hf)-UiO-66 into superhydrophobic Zr(Hf)-UiO-66-SH-y (SH = thiol, y = fluoroalkyl) by introducing long fluoroalkyl chains into organic linkers through a thiol–ene click reaction. Water contact angles of the four modified UiO-66 MOFs are all larger than 150°. The grafted low-surface-energy fluorine-containing groups become an effective protective shield for the MOFs, making them exhibit remarkable stability in extreme conditions such as alkaline (pH = 12), saturated HCl, and high concentration of NaCl solution (20 wt %). The Zr-UiO-66 MOFs grafted with 1H,1H,2H-perfluoro-1-hexene have high CO2 adsorption contents of 1.54 and 2.88 mmol·g–1 at 298 and 273 K, respectively. Moreover, the superhydrophobic MOFs also showed potential application in oil/water separation.