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ORIGINAL PAPER

Preparation and characterization of polypyrrole/graphene nanocomposite films and their electrochemical performance Y. S. Lim & Y. P. Tan & H. N. Lim & N. M. Huang & W. T. Tan

Received: 7 January 2013 / Accepted: 25 April 2013 / Published online: 11 May 2013 # Springer Science+Business Media Dordrecht 2013

Abstract A one-step electrochemical process had been employed to synthesize nanocomposite films of polypyrrole/ graphene (PPy/GR) by electrochemical polymerisation on indium tin oxide (ITO) from an aqueous solution containing pyrrole monomer, graphene oxide (GO) nanosheets and sodium p-toluenesulfonate (NapTS). The X-ray diffraction (XRD) patterns showed that the typical peak of GO at 9.9o was missing from the nanocomposite’s diffraction pattern, suggesting that the GO had been stripped off of its oxygenous groups after the reaction. We postulated that a nanocomposite film was produced through a layer-by-layer deposition based on field emission scanning electron microscope (FESEM) images. The Raman spectroscopy profiles exhibited that the D/G intensity ratio (ID/IG) of PPy was not altered by the inclusion of GO due to the low concentration of the material used. However, the concentration was sufficient to increase the specific capacitance of the nanocomposite by 20 times compared to that of pure PPy, reflecting a synergistic effect between PPy and GR, as analysed by a three-electrode electrochemical cell. The electrochemical performance of the nanocomposites was affected by varying the deposition parameters such as concentrations of pyrrole and GO, scan rate, deposition time and deposition potential. Y. S. Lim : Y. P. Tan : H. N. Lim (*) : W. T. Tan Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia e-mail: [email protected] N. M. Huang Low Dimensional Materials Research Centre, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia Y. P. Tan Centre of Excellence for Catalysis Science and Technology, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

Keywords Supercapacitor . Electrochemistry . Graphene . Polypyrrole

Introduction In the gargantuan effort for energy sustainability, supercapacitors appear to be devices that have received considerable attention due to their superior characteristics which are unmatched by any other charge storage devices. These include higher power density [1], longer life cycle [2], and higher energy density [3] in comparison to conventional electric double layer capacitors (EDLC) [4]. Since portable electronics continue to gain in popularity, the aim to develop an advanced supercapacitor device, a material with high specific capacitance, is indispensable due to its expanding array of applications. Currently, the specific capacitance of the commercial supercapacitor electrode is still less than 200 F/g [5], whereas the specific capacitance of the reported potential supercapacitor electrodes varies from 30– 1,000 F/g [6–13]. Su