CV and EIS studies were performed to evaluate the electrochemical behavior of bare SPE and modified electrodes (rGO/SPE, Co₃O₄/SPE, Pt/SPE, rGO-Co₃O₄/SPE, and rGO-Co₃O₄-Pt/SPE) in 5 mM [Fe(CN)₆]³⁻/⁴⁻ solution prepared in 0.1 M KCl. The electrochemical behavior of the electrodes was evaluted using CV by comparing the cathodic peak current (Ipc) and the potential difference (ΔE) between the anodic and cathodic peaks, as shown in Figure . The unmodified SPE exhibited the lowest cathodic current (Ipc = -34 μA; ΔE = -0.4 V), indicating slow electron transfer kinetics and low electrochemical activity. Modifying the electrode with nanocomposites improved performance. rGO/SPE showed a slight improvement (Ipc = -41 μA, ΔE = -0.3 V), while Co₃O₄/SPE demonstrated further enhancement (Ipc = -48 μA, ΔE = -0.2 V). Pt/SPE achieved Ipc = -53 μA with ΔE = -0.2 V. The rGO-Co₃O₄/SPE modification resulted in the highest current (Ipc = -64 μA) and a low ΔE of -0.2 V. The rGO-Co₃O₄-Pt/SPE electrode exhibited the highest performance, with Ipc = -87 μA and ΔE = -0.3 V, reflecting significant improvements in electron transfer kinetics and reaction reversibility compared to the bare SPE and other modifications. The CV curves show well-defined oxidation and reduction peaks for the redox species, confirming that the electrode operates via a surfacecontrolled process. The Nyquist plot of EIS (Figure ) reveals charge transfer resistance (Rct) and electrochemical behavior. The bare SPE (black) showed the largest semicircle, indicating the highest Rct and poor conductivity. Modified electrodes exhibit progressively smaller semicircles, reflecting improved performance. The rGO/SPE (red) shows reduced Rct, while Co₃O₄/SPE (blue) and Pt/SPE (green) further decrease impedance. The rGO-Co₃O₄/SPE (orange) demonstrates significant improvement due to synergistic effects, and rGO-Co₃O₄-Pt/SPE (olive green) has the smallest semicircle, indicating the lowest Rct. The CV and EIS data demonstrate that the rGO-Co₃O₄-Pt nanocomposite exhibits enhanced current response and reduced charge transfer resistance, making it highly suitable for electrochemical sensing applications.