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One-pot electrochemical synthesis of polypyrrole/graphene oxide composite

Conductive polymers attract significant attention due to the easy synthesis, low cost, high conductivity and fast redox reactions. Polypyrrole (PPy) is one of the most often used conductive polymers in fields such as sensors, electrochromic devices, corrosion protection, actuators and energy power sources. The properties of Ppy can be significantly improved by controlling the microstructure and morphology of the material. In order to achieve fast redox reaction nanometar- sized and porous structure must be considered. Such porous structure could be obtained when polymerization is carried out in the presence of graphene or graphene-based materials [1, 2]. It is expected that Ppy/graphene composite has improved pseudocapacitive properties suitable for supercapacitor application [3]. In this work an electrochemical approach for exfoliation of graphite and synthesis of Ppy/graphene oxide composite was studied. The overall procedure is simple and effective way of graphene synthesis and its intercalation within the polypyrrole layer. The experiments were conducted in two steps. In the first step, graphene oxide was prepared by electrochemical exfoliation of natural graphite flakes. The exfoliation of natural graphite was carried out in sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS) aqueous solutions. Graphite electrode was alternately polarized at positive and negative potentials by using two electrode system. During positive polarization SDS and SDBS intercalate within the structure of graphite, and at the same time oxygen evolution as well as carbon oxidation takes place. By applying negative potential cations intercalate into graphite working electrode and also hydrogen evolution takes place. The overall process resulted in successful exfoliation of graphite electrode. The obtained product, graphene oxide, was characterized by ultraviolet-visible spectrophotometry (UV/Vis), Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). In the second step, monomer was dissolved in a solution obtained during exfoliation process and electrochemical synthesis of Ppy/graphene oxide composites was carried out. The obtained nanocomposite was characterized by means of FTIR and scanning electron microscopy (SEM). The electrochemical measurements were performed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Ion exchange behavior of obtained composite material was also studied by using the electrochemical quartz crystal nanobalance (EQCN).

electrochemical, synthesis, polypyrrole, graphene oxide

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