Water confined in graphene sheets: a fast field cycling NMR study

The production of high-quality graphene sheets is crucial for their practical application in electronics, optoelectronics, energy-storage devices, and composite materials. Among the preparation methods, electrochemical exfoliation of graphite in acidic electrolytes is particularly attractive because of its easy, fast, and environmentally friendly nature. In this work, we aim at assessing the effect of applying different exfoliation voltages on the structure of graphene sheets by using 1H Fast Field Cycling (FFC) NMR relaxometry combined with X-ray diffraction and Raman spectroscopy. The 1H FFC NMR dispersion curves of aqueous suspensions of graphene sheets obtained at different voltages are reported in Figure1. The analysis of the curves enables the assessment of water accessibility to the graphene surface.