Iron Oxide- and Copper Oxide-Decorated Chemically Reduced Graphene Oxide Composite as a Novel Electrode for Hybrid Supercapacitors

In this study, iron oxide- and copper oxide-decorated reduced graphene oxide has been synthesized via a simple wet chemical oxidation–reduction method. The effectiveness of the aforementioned composite as an electrode for supercapacitors (SCs) has been explored via cyclic voltammetry. Raman spectroscopic measurement shows the appearance of a 2D band at 2670 cm–1 and fitting of the 2D band with multiple Lorentzian functions highlights the formation of a few layers of graphenes. Reduced graphene oxide (RGO) formation and the presence of iron and copper oxides on the RGO surface were evident from both X-ray diffraction and energy dispersive spectroscopy results. The thermogravimetric analysis of the synthesized nanocomposite demonstrated superior thermal stability compared to graphene oxide (GO) with almost 60% retention of initial weight after 500 °C. Both the Brunauer–Emmett–Teller test and scanning electron microscopy images established the formation of pores. Average pore diameters of RGO and nanocomposite were observed to be 1.76 and 1.32 nm, respectively. The as-developed nanocomposite exhibited an admirable specific capacitance (Csp) of 626 F/g at a current density of 1.0 A/g. The bimetallic composite demonstrated an excellent energy density of 86.94 Wh/kg.