Hierarchical flower-like Co3O4/ZnO heterojunctions for ppb-level triethylamine sensing in food freshness monitoring

Reliable detection of triethylamine (TEA), a hazardous amine compound, is critical for occupational health and environmental safety. Whilst metal oxide semiconductor sensors are favored for their scalability and low cost, their response and selectivity are often limited. Flower-like Co 3 O 4 /ZnO heterojunction microspheres were synthesised via a solvothermal method, and the experimental results showed that the Co 3 O 4 /ZnO-5 mol% sensor has excellent sensing performance. The response value of 50 ppm TEA at 180°C was 387.2, which was 18 times that of the pure ZnO sensor, and it also exhibited excellent selectivity and good moisture resistance. Furthermore, it has a detection limit of ppb and shows long-term stability. This Co 3 O 4 /ZnO sensor was further applied to food freshness assessment, enabling rapid determination of food freshness through quantitative detection of TEA released during the spoilage of fish and meat. Mechanism studies show that the formation of Co 3 O 4 /ZnO heterojunction enhances electron-hole transfer and charge transfer, continuously promotes oxygen activation into chemisorbed oxygen, and provides active sites for the redox reaction of TEA. This study contributes to the application of TEA sensors and accelerates the development of the integration of experiments and applications.