Microenvironment effect of covalent organic frameworks on chemical catalysis

Inspired by enzymatic catalysis, a variety of covalent organic frameworks (COFs), which have precisely engineered microenvironments enabled by the well-defined porous channels and cavities with catalytically active sites built in, have been developed to mimic the catalytic process of enzymes. The structure diversity and customizability of COFs make them an ideal platform for studying the catalyst structure-activity relationship in heterogeneous catalysis and obtaining a thorough understanding of the catalytic mechanisms. In this review, we summarize the recent progress in the development of COF materials for catalysis applications, with a particular focus on their microenvironment effects. Representative examples of organocatalysis, asymmetric organocatalysis, and metal-supported catalysis utilizing the microenvironment effect enabled by diversified COF ma-terials are discussed. Finally, we outline the key fundamental issues to be addressed and provide our perspectives on the future of COF-based catalysis.