Ionic Liquid-Assisted Exfoliation of Two-Dimensional Metal–Organic Frameworks for Luminescent Sensing

The exfoliation of two-dimensional metal–organic frameworks (2D MOFs) to prepare few-layered MOF nanosheets (MONs) has been of great interest in recent years. In this work, an efficient and environmentally friendly liquid-exfoliation method is developed to produce stable and high-concentration dispersions of few-layered Zn 2 (bim) 4 MONs. Bulk Zn 2 (bim) 4 can be successfully delaminated in ionic liquid and water mixed solvents, where the ionic liquid acts both as solvent and surfactant. The highest exfoliation rate is up to 47% with a [Omim]Cl volume ratio of 50%. In addition, the prepared Zn 2 (bim) 4 MONs can be easily dispersed in an aqueous solution and stabilized for more than 2 weeks. Zn 2 (bim) 4 MONs are used as a fluorescent sensor to detect metal ions in water and exhibit enhanced sensing ability for Fe 3+ than bulk MOFs. The highly dispersive nature after delamination and easily accessible active sites on Zn 2 (bim) 4 MON surface are all in favor of its high-performance in sensing.