Pd-SnO2/In2O3 with a Unique Structure for the Ultrasensitive Detection of Triethylamine near Room Temperature

Triethylamine (TEA) is a serious threat to people’s health, and it is still a challenge to detect TEA at ppb level near room temperature (RT). Herein, we developed a simple, low-cost, low-temperature, and ultra-sensitive TEA sensor based on Pd-SnO2/In2O3 composites. First, SnO2 nanoparticles were obtained by the pyrolysis of Sn-MOF@SnO2 precursor (MOF: metal organic framework), and Pd-SnO2/In2O3 composites were prepared by further compounding and doping. The results show that the Pd-SnO2/In2O3 sensor is highly sensitive to TEA gas at near RT (at 60 °C, the sensor response to 10 ppm TEA is 12,000, the response/recovery (res/rec) time is 51 s/493 s, and at 30 °C, the response value also reaches 1380, the res/rec time is 66 s/610 s), along with good selectivity, stability, and moisture resistance. Even at 10 °C operating temperature and 75% relative humidity (RH) in a low-temperature and high-humidity environment, it still maintains a high sensitivity of over 1000 to 10 ppm TEA, which shows great application potential in TEA detection. The reason for the enhanced performance of the 0.5%Pd-SnO2/In2O3 sensor can be attributed to a large number of adsorbed oxygens on the unique structure of the material, the good charge transfer ability of the n-n-type heterojunction between SnO2 and In2O3, the chemical sensitization and electronic sensitization of Pd nanoparticles, and the catalytic spillover effect. This work will provide a new approach for preparing sensors with good comprehensive properties, making full use of the advantages of the material structure–activity relationship.