Synthesis of Self-Assembled rGO-Co₃O₄ Nanoparticles in Nanorods Structure for Supercapacitor Application

A simple hydrothermal process was used to design self-assembled Co₃O₄ nanoparticles in nanorod structure in the presence of graphene oxide as a template. The as-prepared Co₃O₄ sample in a loose powder form was calcined at 450 °C to get the well-crystalline phase of the same compound. The obtained Co₃O₄ powder sample was characterized by using the powder XRD and SEM. The XRD pattern shows totally nine distinct reflection peaks of (111), (220), (311), (222), (400), (422), (511), (440), and (533) planes. The most intense peaks were chosen to evaluate the structural parameters. The lattice parameters (a), volume (V), and density (ρ) of the samples are 8.09 Å, 529.47 Å³, 6.06 g/cc, which are comparable to the value of lattice parameter (a = 8.056 Å), volume (V = 528.30 Å³), and density (ρ = 6.055 gm/cc) for bulk Co₃O₄. The average size of the Co₃O₄ nanoparticles is 14 nm which is smaller than the SEM size of 50 nm corresponding to the agglomeration of tiny particles. Further, the formation of Co₃O₄ nanoparticles were also confirmed by obtaining the band at 569, 1334,1337, 1566, and 3397 cm⁻¹ in FTIR spectrum. Totally five characteristics peaks from Co₃O₄ at 182.57, 456.49, 505.84, 605.80, and 618.02 cm⁻¹ and peaks from GO-Co₃O₄ at 182.57, 483.44, 505.84, 605.80, and 618.02 cm⁻¹ corresponding to F_2g, E_g, F_2g, F_2g, and A_g modes of the crystalline Co₃O₄, respectively, in the Raman spectra. In the case of GO-Co₃O₄ composite, low-intensity peaks of D and G bands are observed. The specific capacitance in rGO-Co₃O₄ nanocomposite is about 65.15 Fg⁻¹.