MoO 3 Nanorods Decorated by PbMoO 4 Nanoparticles for Enhanced Trimethylamine Sensing Performances at Low Working Temperature.

The gas sensing performance of metal oxides is limited by the lack of conductivity and sensing activity. Inducing the release of more electrons and activating more chemisorbed oxygen ions to participate in the gas sensing reaction can effectively overcome this limitation. The development of a PbMoO 4 /MoO 3 heterostructure prepared by the addition of Pb 2+ ions with MoO 3 nanorods is reported for highly sensitive and selective trimethylamine (TMA) detection. The response of the PbMoO 4 /MoO 3 sensor (33.2) to 10 ppm TMA is improved 3-fold compared to the MoO 3 sensor (10.7), and the working temperature is reduced from 170 to 133 °C. The enhanced gas sensing performance and mechanism of PbMoO 4 /MoO 3 were demonstrated using the energy band diagram and X-ray photoelectron spectroscopy (XPS) analysis. It is mainly attributed to the following promotion: (1) the induction of Pb 2+ ions increases the electron density around the Mo element, enabling the decorated MoO 3 to release electrons easily; (2) the formed PbMoO 4 /MoO 3 heterojunction endows a high degree of electron transfer at the interface; (3) the formation of the potential barrier causes the device resistance to decrease significantly upon TMA exposure. Finally, the practicability of the sensor was verified by detecting TMA released from Carassius auratus and shrimp to reflect their freshness.