Highly Responsive and Swift Recovery Triethylamine Gas Sensor Based on NiCo2O4-ZnO p-n Heterojunction

In the detection of food freshness and chemical production, live tracking of the concentration of triethylamine gas is both essential and challenging. The NiCo2O4-ZnO triethylamine gas sensor prepared with two-step hydrothermal method proposed in this study exhibits a response of TEA at the ideal operational temperature of 250 °C and a response/recovery time of 69 s/2 s. Compared to the single ZnO sensor, the response value is increased by a factor of 8.47, the recovery time is reduced to 1/8, and good selectivity (the response for TEA is 4.75 times higher than others), repeatability, and long-term stability (40 days) are demonstrated. Notably, research on fabricating TEA gas sensors by constructing p-n heterojunctions using NiCo2O4 and ZnO composites is currently lacking. The enhancement of the gas-sensitive properties of the composites is the result of a combination of factors such as increased specific surface area (18.18 m2/g−1) and pore size (29.84 nm), the formation of p-n heterojunctions, and the synergistic effect between the two materials. The excellent TEA sensitivity exhibited by the NiCo2O4-ZnO composites holds considerable practical application potential in triethylamine gas sensors.