Comparative Study of Graphite and the Products of Its Electrochemical Exfoliation

Abstract

A comparative study of electrochemical characteristics of graphite electrodes and precipitates of suspensions produced by the graphite exfoliation is carried out. The graphite is exfoliated into low-layered graphene structures formed in the course of electrochemical impact during the applying of alternating potential to the electrodes. The low-layered graphene structures and graphite electrodes were characterized using numerous procedures from optical, electron, and scanning microscopy, UV-vis-, IR-, Raman, and XPSspectroscopy, and thermogravimetric analysis. The rate constant of electron transfer at the initial graphite for [Ru(NH₃)₆]^2+/3+ and [Fe(CN)₆]^4–/3– redox pairs is shown to approach the value measured both for the lowlayered graphene structures obtained during the graphite electrode exfoliation and for highly oriented carbon nanowalls and single-walled nanotubes measured earlier. At the same time, the Fe^2+/3+ redox-process occurring at the graphite electrode is faster than at the low-layered graphene structures and much faster (by 2–3 orders of magnitude) than at the nanowalls. It is concluded that no significant acceleration of the electron transfer generally occurs when passing from the graphite electrodes to the low-layered graphene structures.