The synthesis of graphene sheets with controlled thickness and order using surfactant-assisted electrochemical processes

An electrochemical route is reported for the production of graphene sheets using the following steps: electrochemical intercalation of sodium dodecyl sulfate (SDS) into graphite followed by electrochemical exfoliation of a SOS-intercalated graphite electrode. These electrochemical processes yield a stable colloidal graphene/SDS suspension. The potential value for SDS intercalation into graphite plays an important role in determining the structural order, size, and number of layers of synthesized graphene sheets. Raman spectroscopy and transmission electron microscopy results indicate that graphene sheets with the highest structural order and lowest number of layers can be obtained by using relatively high intercalation potentials. Average size and thickness of graphene sheets prepared at high potentials for SDS intercalation into graphite were measured to be about 500 and 1 nm, respectively, indicating presence of graphene sheets as thin as a monolayer. UV-vis spectra of graphene/SDS suspensions show that a large amount of the reduced form of graphene flakes is obtained after successive electrochemical intercalation and exfoliation processes. (C) 2011 Elsevier Ltd. All rights reserved.