Freestanding three-dimensional graphene foam gives rise to beneficial electrochemical signatures within non-aqueous media

Abstract

Freestanding three-dimensional (3D) graphene foam has been fabricated via a Chemical Vapour Deposition (CVD) methodology which has a macroscopic structure with microscopic (graphene) features. The 3D graphene macrostructure is characterised with SEM, EDX, XPS and Raman spectroscopy and is found to comprise pristine graphene (O/C of 0.05) which is in the range of mono- to few-layered graphene sheets and is thus termed quasi-graphene. This unique 3D graphene foam is electrochemically explored in both aqueous and non-aqueous solutions and compared to a freestanding 3D reticulated vitreous carbon (RVC) foam alternative. In aqueous solutions, the 3D graphene foam exhibits poor voltammetric responses. Contact angle measurements reveal the 3D graphene to exhibit a value of 120° representing quasi-super-hydrophobicity. Consequently the freestanding 3D graphene foam is found to give rise to significantly improved voltammetric signatures in non-aqueous media (ionic liquids) over that of a freestanding 3D RVC alternative. The 3D graphene foam provides a promising and beneficial architecture over 2D pristine graphene due to its ease of use and macroscopic/microscopic structure, which will have wide implementation in the field of electrochemistry.