Enhancement of electrode performance by a simple casting method using sonochemically exfoliated graphene

We demonstrate within this paper a method for modifying commercial screen-printed electrodes with aqueous graphene suspensions to enhance their electrochemical activity. The graphene suspensions are synthesized by a simple ultrasonic exfoliation method from graphite, where reaggregation is prevented by the addition of common cationic or anionic surfactants, thereby avoiding the use of organic solvents or harsh chemical procedures. These suspensions can then be simply cast onto the screen-printed electrodes. Cyclic voltammetry with a number of redox active species such as phenols, as well as impedance measurements, were made to characterize these systems. The modified electrodes are shown to demonstrate significantly enhanced electrochemical activity and greatly lowered electron transfer resistances compared to the unmodified electrodes. Initial proof of concept applications of these electrodes, including the detection of heavy metals by absorptive stripping voltammetry, are also shown.