Covalent grafting of polyethyleneimine on hydroxylated three-dimensional graphene for superior CO2 capture

Abstract

Covalently tethered CO₂ adsorbents are synthesized by acid catalyzed ring-opening polymerization of aziridine on the basal planes of three-dimensional hydroxylated graphene (HG). The resulting materials possess high surface areas, strong covalent bonds between polyethyleneimine (PEI) and graphene, and high thermal conductivity. The HG–PEI nanocomposites exhibit high amine loading (more than 10.03 mmol N g⁻¹), high adsorption capacity (up to 4.13 mmol CO₂ g⁻¹ in simulated ambient air under 1 atm of dry CO₂) as well as good stability both at low (100 °C) and high desorption temperatures (135 °C), which allows the overall CO₂ capture process to be promising and sustainable.