Aminopolymer functionalization of boron nitride nanosheets for highly efficient capture of carbon dioxide

Abstract

Boron nitrides (BNs) are a class of materials with unique properties that exhibit promise for applications in CO₂ capture. However, the surface electron-deficiency of BNs makes their interaction with Lewis acidic CO₂ very weak. By utilizing the strong interaction between electron-deficient boron atoms and electron-donating amine groups, BN nanosheets were functionalized with polyethyleneimine (PEI) which is rich in amine density, through simple impregnation to improve their performance for CO₂ capture. The important roles of the boron–amine interaction in the incorporation, distribution and stabilization of PEI, as well as the facilitation of CO₂ adsorption and desorption were both experimentally and theoretically investigated. It is demonstrated that after functionalization with PEI, the capacity of pure CO₂ on BN nanosheets was significantly improved (3.12 mmol g⁻¹ for BN functionalized with 54.9 wt% of PEI vs. 0.29 mmol g⁻¹ for pristine BN at 75 °C). Furthermore, the adsorbed CO₂ can be facilely released through N₂ purge at 75 °C, and the PEI-functionalized BN nanosheets exhibit high stability throughout consecutive cycles.