Abstract:

Covalent organic frameworks (COFs) are a type of porous organic polymers with periodic two-dimensional (2D) or three-dimensional (3D) network structures that are designed and assembled by covalently connected structural units, which have the characteristics of high specific surface area, low density, highly ordered periodic structure and easy functionalization. Compared with single-pore COFs, hierarchically porous COFs have hierarchical pore structure, different pore environments, easily accessible active sites, excellent mass transfer and diffusion performance, and show broad application prospects in the fields of gas separation and storage, environmental improvement, photoelectric, biomedicine, catalysis and so on. However, the structural diversity of COFs with hierarchical porosities is still limited due to their harsh synthesis conditions. In this paper, the research progress of COFs with hierarchical porosities is systematically reviewed from the aspects of reaction types, design strategies, synthesis methods, functional modification and application fields. Moreover, the development trend of developing more monomers, bonding types and topologies, expanding more modification methods and giving full play to the advantages of hierarchical pore structure is put forward. In the future, on the basis of continuous exploration and research, more hierarchically porous COFs with new topologies, continuously improve performance and more new applications can be developed, and the rapid, efficient and low-cost processing and molding of COFs with hierarchical porosities can be achieved. As a result, they would play an irreplaceable role in the fields of energy, biology, environment, catalysis and so on.

Key words: covalent organic frameworks, hierarchical porosities, structural design, functional modification, synthetic method

摘要：

共价有机框架（covalent organic frameworks，COFs）是一类通过共价键连接有机构筑单元设计组装而成的具有周期性二维（2D）或三维（3D）网状结构的多孔有机聚合物，具有高比表面积、低密度、高度有序的周期性结构和易于功能化等特点。与单一孔COFs相比，多级孔COFs具有分级的孔道结构、不同的孔环境、极易接近的活性位、优异的传质和扩散性能，在气体分离和储存、环境治理、光电、生物医药、催化等领域具有更为广阔的应用前景。但由于多级孔COFs合成条件苛刻，其结构多样性仍然十分有限。本文从反应类型、设计策略、合成方法、功能化修饰、应用领域等方面系统地综述了多级孔COFs的研究进展，提出开发更多的单体、键合类型、拓扑结构，拓展更多的修饰手段，充分发挥多级孔结构优势的发展趋势。未来通过不断探索与研究，一定能开发出更多具有新的拓扑结构、不断提高的性能及更多新的应用的多级孔COFs材料，实现多级孔COFs快速、高效、低成本的加工成型，使其在能源、生物、环境、催化等领域发挥出不可替代的作用。

关键词: 共价有机框架, 多级孔, 结构设计, 功能化修饰, 合成方法