Rational design of NiCo₂O₄/ZnO hierarchical heterostructures with enhanced triethylamine sensing performance

Triethylamine, a typical volatile marker gas produced during food spoilage, serves as a key indicator of food freshness. Therefore, real-time monitoring of its concentration is of great significance for evaluating food freshness. We synthesize the NiCo 2 O 4 /ZnO using hydrothermal method for triethylamine detection. To characterize the as-prepared samples, XRD, XPS, SEM, XPS, and EIS are used. Among the pure NiCo 2 O 4 , ZnO, and NiCo 2 O 4 /ZnO, the NiCo 2 O 4 /ZnO exhibits (50.2) toward 30 ppm triethylamine, which is around six times higher than that of pure NiCo 2 O 4 at 250 °C. Furthermore, the NiCo 2 O 4 /ZnO composite exhibits rapid response-recovery kinetics, excellent humidity stability, and a favorable selectivity toward triethylamine. The enhanced gas-sensing performance can be attributed to the increased specific surface area, the formation of p–n heterojunctions, and the synergistic interaction between NiCo 2 O 4 and ZnO. These results indicate that the integration of NiCo 2 O 4 with ZnO to create NiCo 2 O 4 /ZnO emerges as an effective approach to enhance the sensing performance of triethylamine.