Improvement of ORR activity of Reduced Graphene Oxide Produced by Thermal Reduction in Basic Media
Podetti Florencia, Zensich Maximiliano, Balach Juan, Morales Gustavo
National University of Rio Cuarto/ Institute of Research in Energy Technologies and Advanced Materials
Reduced graphene oxide (rGO) has attracted research interests in various electrochemical energy conversion reactions due to good electrical properties and high electrochemical surface area. However, the synthesis of graphene oxide (GO) and its reduction process produces a diverse family of compound with different properties; e.g. C/O ratio, nature of oxygenated groups, defects and sheets size distribution, just to mention some of them. Thus, the resulting materials when are used as active electrodes differ in fluidic transport, electron, ion and molecular transport, and local charge-transfer rates. Therefore, it is very important to have in account the structure-property relationships at the moment to design the material for specific device.
We compare different slightly reduced graphene oxide as electrocatalyst for the oxygen reduction reaction (ORR) in alkaline media. A rGO synthesized by thermal reduction in basic (bw-GO) and aqueous media (H2O-GO) shows an
enhancement in the electrocatalytic activity towards ORR compared to an electrochemically reduced graphene oxide (E-GO). The chemical and structural characterization using infrared spectroscopy (FT-IR) and ultraviolet spectroscopy (UV-Vis) revealed a decrease in the oxygen functionalities groups present in the surface of modified GOs. Furthermore, the morphological characterization by atomic force microscopy (AFM) showed important changes in the topography of bw-GO.