Autocatalytic Interfacial Synthesis of Self-Standing Amide-Linked Covalent Organic Framework Membranes

Abstract

The synthesis of crystalline covalent organic frameworks (COFs) has in principle relied on reversible dynamic chemistry. A general method to synthesize irreversibly bonded COFs is urgently demanded for driving the COF chemistry to a new era. Here we report a universal two-step method for the straightforward synthesis of irreversibly amide-linked COF (AmCOF) membranes by autocatalytic interfacial polymerization (AIP). Highly crystalline amide and imine bilinker COF (AICOF) membranes are readily synthesized by AIP strategy which ingeniously leverages interfacial polymerization to generate amide units followed by an autocatalytic condensation that forms imine bonds. Then, the fully amide-linked AmCOF membranes with Turing structures can be prepared through irreversible linker renovation. The universality of this method has been exemplified by nine AmCOF membranes. Among them, the AmCOF-1 membrane exhibits superior performance for H₂O₂ photosynthesis (4353 μmol g⁻¹ h⁻¹) and high stability, enabling continuous production of H₂O₂ under sunlight for 150 h without sacrificial agents. Mechanistic investigations reveal that the greatly improved properties are attributable to the built-in robust amide knots, facilitating full separation of electrons and holes, ultra-long exciton diffusion length, and fast dissociation of excitons within the AmCOF channels.