Synthesis of nitrogen-containing covalent organic framework with reversible iodine capture capability

The use of covalent organic frameworks (COFs) to cope with environmental issues was promising but making them commercial and practical remains a challenge. In this work, we explored the crystallization of a stable nitrogen-containing covalent organic framework (TAPA-PDA COF) and used it as a porous platform for efficient and reversible volatile iodine capture. The TAPA-PDA COF, prepared by simple, rapid, low temperature reactions, possesses a high BET surface area of over 685 m2/g, good crystallinity, high thermal stability and ultrahigh capture of iodine vapor up to 5.09 g/g, which was significantly higher than most reported iodine adsorbents. Although the Raman spectroscopy confirmed the formation of polyiodide compounds through charge transfer between sorbents and iodine molecules, the TAPA-PDA COF still has the ability to be recycled five times while maintaining a high uptake capacity. This study provides promising strategy to solve the difficult problems of commercializing COFs and utilizing them for practical application.