Huang Yan-Li, Ping Lin-Jie, Wu Jie, Li Yan Yan, Zhou Xiao-Ping
College of Chemistry and Materials Science, Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications, Jinan University, Guangzhou 510632, Guangdong, P. R. China.
Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Engineering Technology Research Center of Drug Carrier of Guangdong, Department of Biomedical Engineering, Jinan University, Guangzhou 510632, P. R. China.
Inorg Chem. 2022 Mar 28;61(12):5092-5098. doi: 10.1021/acs.inorgchem.2c00073. Epub 2022 Mar 15.
When compared to industrially stable zeolites, the instability of metal-organic frameworks (MOFs) has been denounced by researchers. Boosting the stability of existing MOFs is highly important for practical applications. In this report, we develop a new strategy to prepare MOFs/poly(tetrafluoroethylene) (PTFE) composites, which can highly improve the chemical, pressure, and photostabilities of zeolitic imidazolate framework (ZIF)-8. Composite materials were prepared by a physical blending of ZIF-8 and PTFE emulsion with different ratios and annealing at 370 °C. Transmission electron microscopy (TEM) studies reveal that the nanoparticles of ZIF-8 are coated by PTFE to form the composite materials. Upon mixing with 20 or 50 wt % PTFE, the ZIF-8/PTFE materials show a superhydrophobic property with water contact angles of around 156°. Pristine ZIF-8 is not stable in water with stirring under acidic, basic, and irradiation conditions, while the ZIF-8/PTFE materials are stable under the same conditions. The ZIF-8/PTFE materials can also maintain their crystalline structure after being compressed with a 10 MPa pressure, while pristine ZIF-8 changes to an amorphous solid after the same pressure treatment. Using water as a solvent, ZIF-8/PTFE can be used as a highly efficient and recyclable catalyst for Knoevenagel reaction at room temperature. The successful preparation of stable ZIF-8/PTFE composite materials provides a useful method to enhance the chemical, pressure, and photostabilities of MOFs.
与工业上稳定的沸石相比，金属有机框架材料（MOFs）的不稳定性一直受到研究人员的诟病。提高现有MOFs的稳定性对于实际应用至关重要。在本报告中，我们开发了一种制备MOFs/聚四氟乙烯（PTFE）复合材料的新策略，该策略可以显著提高沸石咪唑酯框架材料（ZIF）-8的化学稳定性、耐压性和光稳定性。通过将ZIF-8与不同比例的PTFE乳液进行物理共混并在370℃下退火来制备复合材料。透射电子显微镜（TEM）研究表明，ZIF-8纳米颗粒被PTFE包覆形成复合材料。当与20或50 wt%的PTFE混合时，ZIF-8/PTFE材料表现出超疏水性能，水接触角约为156°。原始的ZIF-8在酸性、碱性和光照条件下搅拌时在水中不稳定，而ZIF-8/PTFE材料在相同条件下是稳定的。ZIF-8/PTFE材料在10 MPa压力下压缩后也能保持其晶体结构，而原始的ZIF-8在相同压力处理后转变为无定形固体。以水为溶剂，ZIF-8/PTFE可作为室温下Knoevenagel反应的高效可回收催化剂。稳定的ZIF-8/PTFE复合材料的成功制备为提高MOFs的化学稳定性、耐压性和光稳定性提供了一种有用的方法。
