面向储氢的三维共价有机骨架材料的分子设计与储氢机理研究

Three-dimensional covalent organic frameworks (3D COFs) are considered as idea hydrogen storage materials with great application potential because of their special porous structure and large specific surface area. In this project, we will design novel 3D COFs possessing excellent hydrogen storage properties with the methods of the first principle calculation and grand canonical Monte Carlo. Based on our recent study, the following tasks will be done. (1) We will investigate the microcosmic mechanism of hydrogen adsorption on the building units, especially the adsorption sites, adsorption energy and the interaction mechanism. Then the build units with strong hydrogen adsorption capacity will be selected. (2) The novel 3D COFs will be designed under the direction of the topology structure of corresponding space group and the irreducible representation of the building units. Then the structural stability of 3D COFs will be studied after the geometrical optimization and the 3D COFs with good stability will be used for hydrogen storage. (3) We will characterize the specific surface area, pore volume, pore size and pore distribution of 3D COFs and predict the adsorption, diffusion and desorption of hydrogen gas in these 3D COFs. Then we will systematically study the relation between the hydrogen storage properties and the structures of these 3D COFs, confirm the key factor for hydrogen storage and select the 3D COFs with excellent hydrogen storage capacity. This project can not only deeply uncover the microcosmic hydrogen adsorption mechanism and macroscopic hydrogen storage properties of 3D COFs, but also provide theoretical guidance for the synthesis of novel 3D COFs with excellent hydrogen storage capacity in experiment.

三维共价有机骨架材料（3D COFs）因其独特孔道结构和大比表面等被认为是极具应用潜力的储氢材料。本项目将使用第一性原理计算和巨正则蒙特卡洛方法进行面向储氢的3D COFs分子设计，主要进行以下研究：(1)研究氢分子在COFs构筑单元上的吸附机理，重点研究吸附位、吸附能、吸附作用本质等，筛选出氢分子吸附能力强的构筑单元；(2)在适当空间群对应的拓扑结构导向下，按构筑单元所代表的不可约表示设计出具有相应群对称性的3D COFs，在几何优化基础上筛选出结构稳定的3D COFs；(3)表征3D COFs的比表面积、孔体积、孔道尺寸与分布，预测其氢气吸附、扩散和解吸附性能，系统研究3D COFs结构特征与储氢性能间的构效关系，确定影响储氢的关键因素，筛选出储氢性能优异的3D COFs。本研究不仅能对3D COFs储氢的微观机理到宏观特性进行深刻揭示，还对实验上制备高性能储氢材料具有重要的指导意义。

三维共价有机骨架材料（3D COFs）因其独特孔道结构和大比表面等被认为是极具应用潜力的储氢材料。本项目结合第一性原理计算、分子力学和巨正则蒙特卡洛模拟等方法从理论上设计了几种具有较好储氢性能的3D COFs。首先，我们采用密度泛函理论研究了氢分子与各种化学结构单元的相互作用机理，筛选出了4-氨苯基四面体倍半硅氧烷和三种酸酐单体作为基本构筑单元；然后，在dia、ctn和bor等拓扑结构所属的空间群导向下，按构筑单元所代表的不可约表示设计出了几种3D COFs，在几何优化基础上筛选出结构稳定的3D COFs；最后，对筛选出的COFs材料的密度(0.090-0.247 g/cm3)、氢分子可用表面积(5564.68 - 6754.78 m2/g)、孔体积(4.06 - 10.74 cm3/g)、孔隙率 (92% - 96%)等进行了理论表征，并采用巨正则蒙特卡洛模拟得到了常温及液氮温度下氢气吸附等温线，进一步研究了结构与储氢性能间的构效关系，分析了影响储氢的因素。本项目的顺利开展不仅揭示了所设计3D COFs材料优异的储氢性能，还对相关实验的开展具有很好的指导意义。