Synthesis of Modified Nickel-Cobalt Electrodes on Reduced Graphene Oxide and its Characterization by Scanning Electron Mmicroscopy and Voltammetric Techniques

The electrodes based on metal nanostructures can be used as catalysts in different applications like fuel cells. Catalysts made of bimetallic nanoparticles are superior compared with those made of pure metals, in terms of activity, selectivity, stability, and resistance to poisoning [1]. For example, bimetallic nanoparticles are preferred heterogeneous catalysts in petroleum reforming processes [2]. It is well established that among different metals, nickel because of its surface oxidation properties can be used as a good catalyst. This metal is commonly used as an electro-catalyst for both anodic and cathodic reactions in organic synthesis, water electrolysis and oxidation of alcohols [3]. On the other hand, graphene is a substance with good electrical properties, which can be used in different catalysts. Therefore, in this work, a novel Ni-Co bimetallic structure on reduced graphene oxide (RGO) is constructed. At first RGO is synthesized chemically and then it was used for modification of a carbon paste electrode (CPE). A two-step electrochemically deposition of Co and Ni on the modified electrode was used for preparing the final Ni-Co-RGO electrode. The obtained catalyst (Ni-Co/RGO/CPE) was characterized by scanning electron microscopy and energy dispersive x-ray analysis. Also the electrochemical properties of different electrodes are compared by cyclic voltammetry. The transfer coefficient and charge transfer rate constant were obtained for Ni-Co/RGO/CPE as 0.58 and 0.57 s-1, respectively.