Electrochemical characterization of electrochemically reduced graphene coatings on platinum. Electrochemical study of dye adsorption

Reduced graphene oxide coatings were synthesized by cyclic voltammetry on Pt electrodes. Electrochemically reduced graphene oxide was analyzed by scanning electrochemical microscopy for the first time. The redox mediator influences the electrochemical response; thus Ru(NH3)(6)(3+) and Fe (CN)(6)(3) gave a similar response and Fe3+ gave the poorest response. Pt electrodes coated with reduced graphene oxide were also used in the electrochemical adsorption (performed by cyclic voltammetry) of different dyes (Methylene Blue, Procion MX-2R and Amaranth). Electrochemical methods proved to be useful to monitor the adsorption of dyes on the surface of graphene materials. After adsorption, with Methylene Blue and Procion MX-2R, the appearance of a stable redox pair (with 1 electron transfer) was observed. This redox pair was adsorption controlled since the intensity of the redox pair was proportional to the scan rate used. Electrochemical adsorption multiplied by 3 the electrical charge of the Methylene Blue adsorbed on the surface of reduced graphene oxide when compared with simple adsorption at open circuit potential. In the case of Procion MX-2R, the increase obtained was even higher, with a 6-fold increase. (C) 2015 Elsevier Ltd. All rights reserved.