Exfoliated covalent organic framework nanosheets

Abstract

Covalent organic frameworks (COFs) are an emerging type of crystalline porous organic polymers with well-defined network structures and designable pore sizes, which have been applied in many fields such as gas storage and separation, energy storage, catalysis, and sensing in recent years. However, most synthesized COFs are obtained in the form of insoluble bulk powder, which greatly hinders their processing/assembly into functional devices. Accordingly, preparing COF nanosheets is a strategy that is expected to solve the processability issues of bulk COFs owing to the favorable dispersion of nanosheets in various solvents. Exfoliating COFs into single/few-layered nanosheets is a simple and effective way to prepare exfoliated nanosheets (eNSs). In recent years, the increasing number of strategies for the preparation of eNSs and their subsequent applications have greatly propelled the development of COFs. This review mainly summarizes the various achievements in the preparation of eNSs from bulk COFs, and the related developments in the applications using these eNSs. In addition, some challenges and opportunities for the future development of eNSs are also presented.