用于高效碘吸附的甲基化共价有机框架的简易合成

Facile Synthesis of Methylated Covalent Organic Framework for Efficient Iodine Uptake

以2,4,6-三甲基苯-1,3,5-三甲醛和2,5-二甲基对苯二胺作为单体构建了一种新型的甲基化共价有机框架材料(COF-946)。利用傅里叶变换红外光谱仪(FT-IR)、粉末X射线衍射仪(PXRD)、氮气吸附/脱附等温线、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等对COF-946的基础结构和性能进行了表征。结果表明:COF-946具有较高的碘蒸气吸附量(5.65 g/g)和吸附速率(0.78 g/(g·h)),并且在经历了5次循环后依旧可以保持90%以上的原始吸附能力。

Covalent organic frameworks(COF)is crystalline organic polymers with periodic architectures and well-defined pores,enabling various applications such as gas storage and separation,catalysis,sensor and energy storage.Crystallinity and porosity are two important properties that determine the performance of COF,and the preparation of COF with high crystallinity and specific surface area has been a key issue in the synthesis of COF.Herein,a novel methylated covalent organic framework material(COF-946)was constructed using 2,4,6-trimethyl-benzene-1,3,5-tricarbaldehyde and 2,5-dimethyl-p-phenylene diamine as building blocks.The methylation not only significantly enhances the crystallinity and porosity by preventing pore collapse,but also allows COF-946 to be prepared in a variety of solvent systems.The basic structure and properties of COF-946 were characterized using Fourier transform infrared(FT-IR)spectroscopy,powder X-ray diffraction(PXRD),nitrogen adsorption/desorption isotherms,scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Results show that COF-946 with high crystallinity and specific surface area can be prepared in a wide range of solvents and within a short period of time(SBET>700 m^(2)/g in 0.5 h).In addition,COF-946 has a high iodine vapor adsorption capacity(5.65 g/g)and adsorption rate(0.78 g/(g·h)),and can maintain more than 90%of the original adsorption capacity after five cycles.