Bio-reduction of graphene oxide using drained water from soaked mung beans (Phaseolus aureus L.) and its application as energy storage electrode material

•Green reduction of GO using mung bean soaked water has been demonstrated.•The isolation of reduced is very simple and precludes extra purification process.•The specific capacitance of rGO is 137 F g−1 at a current density of 1.3 A g−1.•The retention in specific capacitance is ∼98% after 1000 charge–discharge cycles.

Green reduction of graphene oxide (GO) using drained water from soaked mung beans (Phaseolus aureus L.) has been demonstrated. In comparison to the toxic and hazardous reducing chemicals, the drained water from soaked mung beans (P. aureus L.) is completely green reducing agent, the reduction process is very simple and cost effective. The removal of oxygen containing functional groups of GO has been confirmed by UV–vis, Fourier transform infrared and X-ray photoelectron spectroscopy analysis. Morphological characterization of rGO has been performed by atomic force and transmission electron microscopy analysis. Electrochemical performances of rGO have been evaluated by cyclic voltammetry (CV), charge–discharge and electrochemical impedance spectroscopy techniques. The specific capacitance (SC) of rGO has been found to be 137 F g−1 at a current density of 1.3 A g−1. The retention in SC is more than 98% after 1000 charge–discharge cycles suggesting long-term electrochemical cyclic stability as supercapacitor electrode materials.

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