Catalyst-Free Synthesis of Porous Graphene Networks as Efficient Sorbents for CO2 and H-2

Abstract

Reported is a catalyst-free synthetic route for the preparation of porous graphene networks (PGNs) incorporating benzimidazole linkages through the condensation reaction between ester-functionalized graphene sheets and organic aromatic amine linkers. PGNs showed remarkable thermal stability at temperatures of up to 350 degrees C in air. This emphasizes the importance of the formation of robust CC bonds by means of the Johnson-Claisen rearrangement for the covalent functionalization of graphene layers. PGNs exhibited high surface areas up to 732m(2)g(-1) and showed the highest CO2 uptake capacity (3.75mmolg(-1) at 273K, 1bar) along with a remarkable CO2/N-2 selectivity (130 at 273K, 1bar) of all the GO and graphene frameworks reported to date. PGNs as low-cost, efficient solid sorbents also exhibited high affinity towards H-2 (1.2wt% at 77K, 1bar).