Cerium vanadate/graphitic carbon nitride nanocomposite for electrochemical detection of diphenylamine

• Synthesis of CeVO 4 nanoparticles mediated by quaternary ammonium surfactants. • Electrochemical detection of DPA using by CeVO 4 /g-C 3 N 4 hybrid composite. • Synergistic interaction between CeVO 4 and g-C 3 N 4 promotes electrocatalytic activity. • The fabricated sensor showed a linear range of 0.01 to 792 µM and low LOD of 1.1 nM. • CeVO 4 /g-C 3 N 4 shows good recovery range of ±96.4–99.7 % from spiked real samples. Physiological storage issues in fruits often result from inadequate post-harvest handling. Diphenylamine (DPA), commonly used to prevent surface scald, may leave toxic residues, necessitating precise detection. In this study, cerium orthovanadate (CeVO 4 ) was synthesized via a hydrothermal route and characterized using XRD, FTIR, HRTEM, and XPS. A CeVO 4 @g-C 3 N 4 nanocomposite was fabricated and drop-cast onto a screen-printed carbon electrode (SPCE) for electrochemical sensing of DPA. Sensor performance was evaluated using EIS, CV, and DPV, along with optimization of catalyst loading, scan rate, pH, and stability. The CeVO 4 @g-C 3 N 4 -modified SPCE showed a wide linear detection range (0.01–792.0 µM), low detection limit (1.1 nM), and high sensitivity. Real fruit sample analysis demonstrated high recovery and reliability. The study's novelty lies in the use of CeVO 4 @g-C 3 N 4 as a sensitive and reproducible sensing interface, offering a practical platform for DPA detection in food safety monitoring.