Two‐Dimensional MOF and COF Nanosheets: Synthesis and Applications in Electrochemistry

Metal–organic framework (MOF) and covalent organic framework (COF) nanosheets are a new type of two‐dimensional (2D) materials with unique design principles and various synthesis methods. They are considered ideal electrochemical devices due to the ultrathin thickness, easily tunable molecular structure, large porosity and other unique properties. There are two common methods to synthesize 2D MOF/COF nanosheets: bottom‐up and top‐down. The top‐down strategy mainly includes ultrasonic assisted exfoliation, electrochemical exfoliation and mechanical exfoliation. Another strategy mainly includes interface synthesis, modulation synthesis, surfactant‐assisted synthesis. In this Review, the development of ultrathin 2D nanosheets in the field of electrochemistry (supercapacitors, batteries, oxygen reduction, and hydrogen evolution) is introduced, and their unique dimensional advantages are highlighted. Materials for electrochemistry: Metal–organic framework and covalent organic framework nanosheets represent one promising kind of power materials for electrochemical. Synthesis strategies, tailored material properties and different electrochemical performances are prominent features of supercapacitors, batteries, OER and HER. Metal–organic framework and covalent organic framework nanosheets comprehensively summarized and evaluations are given in this Review.