Enhanced electrochemical and optical properties of rGO-Integrated Cu-Zn-Dy ferrites nanocomposites for energy storage and catalysis applications

The electrochemical, structural, and optical properties of (x)rGO + (1-x)Cu-ZnDy₀.₀₂Fe₁.₉₈O₄ nanocomposites were systematically investigated to explore their potential in supercapacitor and electrocatalysis applications. The X-ray diffraction (XRD) analysis confirmed the presence of a spinel Cu-Zn ferrite phase, with lattice parameter variations indicating slight structural distortions induced by rGO incorporation. The Fourier-transform infrared spectroscopy (FTIR) analysis revealed characteristic Fe–O, Cu–O, and Zn–O vibrations, along with decreasing oxygen functional groups with increasing rGO content, suggesting effective deoxygenation and improved electrical conductivity. X-ray fluorescence (XRF) analysis confirmed the successful incorporation of Fe, Cu, Zn, and Dy into the nanocomposite structure. The UV–Vis diffuse reflectance spectroscopy (DRS) analysis demonstrated that the bandgap energy varied from 2.05 eV (rGO 0.25) to 1.87 eV (rGO 1.0), with a gradual decrease in bandgap with increasing rGO content. This trend suggests enhanced electronic conductivity and light absorption, making the material suitable for optoelectronic and photocatalytic applications. Electrochemical measurements, including linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and capacitance measurements, revealed significant improvements in charge storage and conductivity with increasing rGO content. The rGO(0.5) sample exhibited the lowest Tafel slope (127 mV/dec), lowest charge transfer resistance (R_ct), and highest electrochemical stability, making it the most promising candidate for electrochemical applications. The Nyquist plot and capacitance analysis confirmed that rGO(0.5) and rGO(0.75) compositions provided the best balance between conductivity and active site availability. These findings highlight the importance of optimizing rGO content in Cu-ZnDy ferrite systems to enhance electrochemical performance, improve charge transfer properties, and expand applications in energy storage, catalysis, and electronic devices. The optimized rGO(0.5) composition demonstrated the highest overall electrochemical efficiency, making it a viable candidate for next-generation supercapacitors and hybrid energy storage systems.