Developing non‐noble‐metal electrocatalyst for non‐enzymatic H2O2 sensing is highly attractive. A facile, two‐step approach has been utilized for the synthesis of PBNCs/SnO2 QDs/RGO ternary nanocomposite. TEM, SEM, XPS, and XRD techniques were used to the characterize the structural and morphological properties of synthesized ternary nanocomposite. The synthesized ternary nanocomposite has been examined as an electrode material for the electrochemical detection of H2O2 using the Amperometry technique. Under optimum conditions, PBNCs/SnO2 QDs/RGO ternary nanocomposite performed very well in the electrocatalytic reduction of H2O2 with a linear dynamic range from 25–225 μM (R2=0.996) with a low detection limit of 71 nM (S/N=3). Compared to the recent literature, PBNCs/SnO2QDs/RGO ternary nanocomposite based modified electrode exhibit a wider linear dynamic range with a low detection limit. Furthermore, PBNCs/SnO2 QDs/RGO ternary nanocomposite based modified electrode showed an excellent anti‐interference ability against various common interfering agents. The practical applicability of this ternary nanocomposite based modified electrode was further extended to determine the H2O2 in tap water with acceptable recovery. The present performance of PBNCs/SnO2 QDs/RGO ternary nanocomposite material towards H2O2 sensing might widen its application for developing a new type of non‐noble metal‐based non‐enzymatic electrochemical biosensors.

An electrochemical sensor has been developed using PBNCs/AuNPs/RGO ternary nanocomposite, in which gold nanoparticles (AuNPs) are deposited on Prussian blue nanocubes (PBNCs) and reduced graphene oxide (RGO) using two‐step in‐situ synthetic approach. The synthesized ternary nanocomposite shows high catalytic activity towards H2O2 sensing due to the synergistic effect of gold nanoparticles and RGO. The material was prepared by the co‐precipitation method, and the morphology of the synthesized composites was characterized using X‐Ray diffraction (XRD), scanning electron microscopy (SEM), and High‐resolution Transmission electron microscopy (HR‐TEM). Electrochemical measurements were performed by modifying glassy carbon electrodes (GCE) with bare PBNCs, PBNCs/RGO, and PBNCs/AuNPs/RGO for low‐level detection of H2O2 using Cyclic Voltammetry (CV) and Chronoamperometry. The interference property was analyzed using ascorbic acid (AA), uric acid (UA), and glucose as interfering agents. The modified electrode shows high sensitivity of 5.47 nA/nM and a limit of detection of 260 pM for H2O2 at (S/N=3). This electrochemical sensor observed a linear range of detection from 0.66 nM to 10.53 nM. The proposed sensor exhibits good stability, better selectivity, and a picomolar concentration detection limit for H2O2.