Effective Combination of rGO and CuO Nanomaterials through Poly(p-phenylenediamine) Texture: Utilizing It as an Excellent Supercapacitor

The foremost objective of this work is to fabricate a novel design nanoscale composite made of reduced graphene oxide (rGO), copper oxide (CuO) nanoparticles, and poly(p-phenylenediamine) (PpPD) (named rGO/CuO/PpPD) and to investigate its characteristics as an electrode in a three-electrode electrochemical arrangement for the functional improvement of the supercapacitors. GO is synthesized via a modified Hummers process and then it is converted to rGO via a hydrothermal method. Moreover, the CuO nanoparticles are synthesized and effectively combined with pPD in the presence of ammonium persulfate (APS) for the in situ polymerization to PpPD, as a conducting polymer. The obtained composite is then immobilized on rGO surfaces in a ratio of 2:1:1 of rGO, CuO, and PpPD, respectively. In fact, since the in situ polymerization leads to a tighter structure, a close packing of the ingredients is obtained in the coated electrode structure with good integration. The prepared rGO/CuO/PpPD nanocomposite is structurally characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Besides, the electrochemical performance of the prepared nanocomposite is also studied through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and cyclic charge/discharge (CCD) technique. As an outstanding result, it is observed that the specific capacitance is remarkably increased to 512.12 F/g (at 1 A/g) on applying the rGO/CuO/PpPD-coated electrode with cyclic stability improved to 10 000 cycles.