Nanographene Aerogels: Size Effect of the Precursor Graphene Oxide on Gelation Process and Electrochemical Properties

Abstract

Improving the electrochemical properties of graphene aerogels (GAs) without doping or making composites is an attractive synthetic strategy. In this work we report on the effects of graphene sheet dimensions on GAs. Nanographene aerogels (nG-AGs) were synthesized using nanographene oxide (nGO) powder with a mean platelet diameter of 90 nm. In-situ Fourier transform infrared spectroscopy (FTIR) during gelation revealed a longer fast gelation regime for nG-AGs than for stdG-AGs. The surface-area-normalized capacitance of nG-AGs calculated from cyclic voltammetry is 16% higher than that of stdG-AGs, and the onset of hydrogen evolution is observed at a lower over-potential. These observations can be attributed to increased edge sites and defects in nanographene sheets. Our results imply that the diameter of the precursor graphene sheets can be used as a parameter to optimize the electrochemical properties of graphene AGs depending on the application.

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