Ultrafast photodegradation of methylene blue dye and supercapacitor applications of flower like hydrothermal synthesized V2O5 nano -structures on rGO as nano - composite

In recent years, studies into the energy storage and water remediation are on the top priority of material scientists. Development of graphene-based materials for the purpose is a novel attempt in current research. Novel rGO - V2O5 nano composite having excellent photocatalytic and supercapacitor properties was designed and characterized in the present manuscript. V2O5, reduced graphene oxide (rGO) and rGO-V2O5 composite (with concentrations 1:0.5, 1:1, 1:2, and 1:3), were synthesized by hydrothermal method, standard modified Hummer's method followed by Hydrazine based reduction and sonochemical method, respectively. All the compounds were characterized by X-ray diffraction (XRD), Raman spectroscopy and Scanning Electron Microscopic techniques to study the structural and morphological aspects. Photocatalytic dye degradation experiments for Methylene Blue dye degradation and Electrochemical studies including cyclic voltammogram (CV), Galvanostatic Charging and Discharging (GCD), Electrochemical Impedance Analysis (EIS) experiments were performed on these compounds. XRD and Raman studies confirm the successful synthesis of these compounds and SEM images manifest excellent distribution of nano V2O5 on rGO sheets. At the concentration of 1:1, the rGO-V2O5 composite exhibits an ultrafast degradation of MB up to 94% under visible irradiations in just 8 min because of its narrow bandgap (2.4 eV) compared to the bare rGO (51%@135) and V2O5 (15%@22), respectively. Trappingactive-species experiment was performed to understand the MB degradation mechanism with rGO-V2O5, where the superoxide ion role has been found to be superior to other elements present in the degradation reaction. The optimized rGO-V2O5 (1:1) composite was further employed in the supercapacitors, showing a higher specific capacitance (Cs) of 818 F/g than that of the bare rGO (548 F/g) and V2O5 (246 F/g) at the 1 A/g of current density in 3 M KOH aqueous electrolytes. The results manifest ultrafast degradation and superior electrochemical performance for the designed composite of rGO and V2O5.