Electrochemical responses of the electrodes were evaluated via CV with and without 5 mM H₂O₂ in 0.1 M KCl (Figure ), revealing significant differences in H₂O₂ detection. In bare SPE, an electrochemical current of -16 ± 0.2 μA was observed, which increased slightly to -21 ± 0.4 μA upon the addition of 5 mM H₂O₂, indicating limited catalytic activity and poor sensitivity. For the rGO-modified electrode, the current was -11 ± 0.4 μA, rising to -22 ± 0.3 μA with H₂O₂, showing improved but still modest activity. Further, for Co₃O₄/SPE, the current was -18 ± 0.4 μA, which significantly increased to -35 ± 0.4 μA upon H₂O₂ addition, demonstrating its electrocatalytic capability for H₂O₂ reduction. The Pt/SPE showed an even stronger performance, with a current of -22 ± 0.2 μA that rose dramatically to -51 ± 0.4 μA in the presence of H₂O₂. The rGO-Co₃O₄/SPE achieved further enhancement, with an initial current of -23 ± 0.2 μA increasing to -54 ± 0.2 μA upon H₂O₂ addition, highlighting the synergistic effect of combining rGO with Co₃O₄. Among all tested electrodes, the rGO-Co₃O₄-Pt nanocomposite-modified SPE demonstrated the best performance, with a current of -31 ± 0.3 μA and a significant increase to -71 ± 0.4 μA after H₂O₂ addition. This improvement is attributed to the synergistic effects of the rGO, Co₃O₄, and Pt components, enhancing catalytic activity and electron transfer.