Tailor-made pore surface engineering in covalent organic frameworks: systematic functionalization for performance screening

Abstract

Imine-linked Covalent Organic Frameworks (COFs) were synthesized to bear content-tunable, accessible, and reactive ethynyl groups on the walls of one-dimensional pores. These COFs offer an ideal platform for pore-wall surface engineering aimed at anchoring diverse functional groups ranging from hydrophobic to hydrophilic units and from basic to acidic moieties with controllable loading contents. This approach enables the development of various tailor-made COFs with systematically tuned porosities and functionalities while retaining the crystallinity. We demonstrate that this strategy can be used to efficiently screen for suitable pore structures for use as CO₂ adsorbents. The pore-surface-engineered walls exhibit an enhanced affinity for CO₂, resulting in COFs that can capture and separate CO₂ with high performance.