Concentration studies up to 5 mM were conducted using the CV technique at a scan rate of 50 mV/s (Figure ), following the confirmation of the strong electrocatalytic performance of rGO-Co₃O₄-Pt/SPEs for H₂O₂ reduction. The CV curves reveal a linear rise in peak current with increasing H₂O₂ concentrations (see insert i), signifying a diffusion-controlled electrochemical process. This indicates the effective interaction of H₂O₂ with the electrode surface, enabled by the high surface area of rGO, the catalytic properties of Co₃O₄, and the enhanced sensitivity provided by Pt. A sensitivity of 6.01 ± 0.17 μA mM⁻¹ (R² = 1) indicated a strong linear correlation between cathodic current and hydrogen peroxide concentration. However, CV is less suitable for quantitative analysis due to lower sensitivity, broader peaks, and higher background currents, which reduce the accuracy. To overcome these limitations, SWV was used, offering sharper peaks, enhanced faradaic signals, and reduced background interference for improved quantitative analysis . concentration. Experimental conditions: t equilibration=0 s, E begin = -0.8V; E vertex1 = -0.8 V; E vertex2 = 0.8 V; E step = 0.01 V; scan rate = 0.05 V/s. (B) SWV of the electrochemically activated rGo-Co3O4-Pt/SPEs in 0.1 M KCl containing different concentrations of H2O2 (up to 2.5 µM). Inset (ii) shows the calibration curve of current versus H2O2 concentration, confirming a strong linear correlation in the lower micromolar range. Experimental conditions: t equilibration=0 s, E begin = 0.0 V; E end = -0.6 V, E step=0.001 V; with an amplitude of 0.025 V and a frequency of 25.0 Hz.