Structure and Dynamics in Functionalized Graphene Oxides through Solid-State NMR

Abstract

Graphene oxide (GO), a derivative of the supermaterial graphene, has intrinsic proton conductivity, which is similar to Nafion, the most popular proton exchange membrane material currently used in fuel cells. Research into acid-functionalized GOs and determining the role of acidic groups in increasing proton conductivity will help to improve polymer electrolyte membrane performance in fuel cell systems. Multinuclear solid-state NMR (ssNMR) spectroscopy was used to analyze the structure and dynamics of GO and a number of sulfonic acid derivatives of GO, both novel and previously reported. 13C CP-MAS spectra showed the disappearance of surface-based oxygen groups upon GO functionalization and can be used to identify linker group carbon sites in previously synthesized and novel functionalized GO samples with high specificity. Dehydration of these samples allows the collection of 1H spectra with resolved acidic proton and water peaks. The effect of dehydration on the proton spectrum is partially reversible th...