Boosting Hydrostability and Carbon Dioxide Capture of Boroxine-Linked Covalent Organic Frameworks by One-Pot Oligoamine Modification

Abstract

Boron-based covalent organic frameworks (COFs) are susceptible to nucleophilic attack by water at the electron-deficient boron sites and even slightly humid air could destroy the integrity of their porous frameworks within hours. Such instability is a major limitation to the practical applications of boron-based COFs. Herein we report a significant enhancement of hydrostability of boroxine-linked COFs (COF-1 as representative) by modification with an oligoamine (tetraethylenepentamine, TEPA), which leads to survival of the modified COF in water and long-time stability under humid atmosphere. Meanwhile, the TEPA modification also results in a considerable increase in CO₂ adsorption capacity up to 13 times and a dramatic improvement in CO₂ /N₂ selectivity in low pressure region, which make the modified COF suitable for capturing CO₂ from flue gas. This work provides a facile, efficient, and scalable method to greatly improve hydrostability of boroxine-linked COFs and reshape them into high-performance CO₂ adsorbents.

Keywords: COF-1; carbon dioxide capture; covalent organic frameworks; hydrostability; oligoamine.