Multifunctional Ternary Nanocomposites of Ni/Polypyrrole/Reduced Graphene Oxide as Supercapacitor and Electrocatalyst in Methanol Oxidation

In this work the concurrent electrochemical energy storage and conversion characteristics of Ni nanoparticles supported on polypyrrole-reduced graphene oxide (Ni/PPy/rGO) nanocomposite is reported. Ni/PPy/rGO nanocomposite was synthesized by mixing its precursors PPy/rGO and NiCl2 center dot 6H(2)O, where Ni2+ was reduced to Ni at pH 10.5. The obtained nanocomposite is characterized using FTIR, XRD, Raman Spectroscopy, SEM and dynamic light scattering methods. The electrochemical energy storage properties of the nanocomposite are investigated using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy tests. Electrochemical analysis reveals that Ni/PPy/rGO nanocomposite has high specific capacitance of 763.49 Fg(-1) at 1.31 Ag-1 current density with capacity retention of 96.75% after 200 cycles Ni/PPy/rGO nanocomposite is also used as electrode in methanol electro-oxidation. Cyclic voltammetry and chronoamperometry are carried out to study the electrochemical energy conversion properties of the composite towards methanol electro-oxidation. The anodic current density of the Ni/PPy/rGO nanocomposite is much higher than that of Ni/rGO and PPy/rGO. Moreover, the onset potential of Ni/PPy/rGO nanocomposite is much lower than that of Ni/rGO and PPy/rGO. The results show that the Ni/PPy/rGO nanocomposite is electro-catalytically active and highly stable.