Pr ³⁺ -Doped WO ₃ 1D Yoga-Pillar-Shaped Nanorod Gas Sensor: A High-Performance Ppb-Level Triethylamine Gas Sensor for Fish Freshness Monitoring

Traditional triethylamine (TEA) gas sensors suffer from the drawback of high detection limits due to the low charge-transfer ability of materials. Herein, the Pr 3+ -doped WO 3 one-dimensional (1D) yoga-pillar-shaped nanorods have been successfully synthesized via electrostatic spinning and oxidative calcination. The gas sensor based on WO 3:1%Pr 3+ 1D yoga-pillar-shaped nanorods exhibits excellent performance in terms of rapid response (3-fold), higher response (3.75-fold), and lower detection limits compared with the WO 3 gas sensor. Furthermore, the sensor features excellent repeatability and long-term stability, indicating the potential commercial value. The findings reveal that doping Pr 3+ is one of the effective strategies to improve the gas-sensing performance of WO 3 . Based on the above analysis, as well as literature reports, the gas-sensing mechanism is explored systematically. The enhancement can be attributed to the formation of impurity energy levels, which can effectively optimize the band structure and facilitate electron transfer. The recombination between electrons in the conduction band and holes in the valence band is partly suppressed, providing more opportunities for electron exchange between WO 3 and oxygen molecules. The content of chemically adsorbed oxygen on the WO 3 surface has significantly increased, which is one of the fundamental reasons for the improvement in gas sensitivity. In addition, the practical value of the WO 3:1%Pr 3+ 1D yoga-pillar-shaped nanorod gas sensor is demonstrated by testing the freshness of fish stored under various conditions. This work presents a high-performance ppb-level TEA detection method and broadens the application scope of WO 3 gas sensors.