Nitrogen-doped bismuth molybdenum carbide: A superior heterojunction catalyst for electrochemical nitrite sensing in food

In this work, we developed a high-performance electrochemical sensor for sensitive and selective detection of nitrite in environmental and food samples, utilizing bismuth-modified nitrogen-doped molybdenum carbide nanocomposites (Bi@N-Mo₂C) as the active material The nanocomposite was synthesized through a two-step process involving the formation of Bi@PD-Mo hollow spheres via self-assembly polymerization, followed by thermal carbonization to yield Bi@N-Mo₂C. The resulting material was immobilized on a glassy carbon electrode, enhancing electrochemical activity, as confirmed by Cyclic voltammetry and differential pulse voltammetry through its excellent sensitivity, reproducibility, and long-term stability. Sensor exhibited a broad linear detection range (14.9 μM-3.8 mM) and an ultralow detection limit of 0.13 μM. Its practical applicability was demonstrated by successful nitrite detection in real samples including milk, apple juice, and tap-water. The sensor also showed high selectivity and robustness in complex environments, indicating its potential as a reliable platform for food safety and environmental monitoring.