Different metal oxides (MOs) nanomaterials of ZnO, SnO2, and nanocomposites ZnO:SnO2 with various ratios of (1:9), (2:8), and (3:7) were prepared and coated on GCE. All MOs were tested as sensing materials for organophosphate pesticide detection. Among all MOs, ZnO:SnO2 (1:9) coated GCE increases redox peak current at different buffer solutions with varying pH compared to bare and coated GCE. Among different pH, ZnO:SnO2 (1:9) coated GCE significantly enhanced the redox peak at pH 6.2, emphasizing optimal electrochemical conditions for pesticides. Moreover, among these pH values, ZnO:SnO2 (1:9) coated GCE significantly enhanced the redox peak at pH 6.2, emphasizing optimal electrochemical conditions for the given pesticides. The morphological, elemental compositions and structural characterization of different MO nanomaterials were examined using field-emission scanning electron microscopy (FESEM), energy dispersive X-ray spectrum (EDX), and X-ray diffraction (XRD), which was further carried out to evaluate the electrocatalytic activity towards DiZn sensing. Furthermore, the electrochemical behavior of the ZnO:SnO2 (1:9) coated GCE was evaluated using cyclic voltammetry (CV) with 0.5 mL (5 mM) potassium ferrocyanide, resulting a pronounced increase in anodic and cathodic peak potentials (Epa = 0.423 V, Epc = 0.1945 V) and currents (Ipa = 9.867 × 10-5 mA, Ipc = -7.993 × 10-5 mA). In addition, electrochemical impedance spectroscopy (EIS) demonstrated a reduction in charge transfer resistance, which enhanced conductivity. Differential pulse voltammetry (DPV) further showed a linear relationship between current and pesticide concentration, with a high correlation coefficient (R = 0.996), low limit of detection (LOD = 0.0133 mM) and low limit of quantification (LOQ = 0.0405 mM). Real samples, including tap and seawater, were analyzed to validate the method’s applicability. Additionally, chronoamperometry with a step potential of 1.2 V indicated high sensitivity for DiZn detection, with a sensitivity of 0.23 mA mM−1 cm−2. Finally, the stability of the ZnO:SnO2 (1:9) coated GCE was confirmed through recyclability tests over three cycles using CV and DPV techniques, ensuring its robustness for practical applications in pesticide detection.