Nano-Engineered Spacing in Graphene Sheets for Hydrogen Storage

Abstract

Thermally exfoliated graphene (TEG) sheets were functionalized and cross-linked by in situ diazonium reactions in super acids. The degree of functionalization was monitored by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Compared with the original TEG material, the functionalized TEGs show improved hydrogen uptake capacities, which could be attributed to the proppant effect of the grafted functional groups and charge transfer between the sulfonic addends and the graphene sheets. This method provides a possible route to further increase the hydrogen storage capacity of graphene materials by cross-linking and nanospace engineering.