Effects of Intercalated Molecules in Graphene Oxide on the Interlayer Channels for Anhydrous Proton Conduction

Abstract

Herein, 11 kinds of graphene oxide (GO)-based nanocomposites are prepared by intercalating organic molecules bearing different functional groups into GO layers. The changes of d-spacing (Δd) of GO upon intercalation suggest that Δd is mutable and regulated dynamically by surrounding environment, and organic molecules are mainly located in the cavities of GO. The conducting groups allow organic molecules to act as additional proton hopping sites and to connect hydrogen bonds networks within GO, endowing the resultant nanocomposites with enhanced proton conduction abilities. The proton conductivities vary with functional groups on organic molecules, increasing in the order of GO/phenol < GO/benzoic acid < GO/benzenesulfonic acid < GO/phenylamine. Increasing the amount of functional groups or optimizing the ligand structure will further enhanced the proton conduction ability. Particularly, GO/4-aminobenzoic achieves the highest proton conductivity of 5.0 × 10–4 S cm–1 under 30 °C and anhydrous condition, 10 times higher than that of GO.