Advanced triethylamine sensor utilizing 3D microspheres of La-doped MoO3: Performance enhancement and mechanism insights

Triethylamine (TEA) as an excellent solvent, polymer inhibitor and preservative often appears in various places in industrial production, but its harm can not be underestimated. For the detection of TEA, molybdenum trioxide (MoO3) is a great gas-sensitive material, but its response and recovery time are long. In addressing improvements to MoO3, the paper introduced a method involving the introduction of the rare earth metal La and further pinpointed an optimal doping concentration strategy. In this paper, three-dimensional (3D) microspheres of La-doped MoO3 with different doping concentrations were synthesized using a facile hydrothermal method. Among these, the sensor based on 1 wt% La-doped MoO3 exhibits the highest gas-sensing response to TEA, with a response value of approximately 30–20 ppm TEA when the temperature is 240 ℃, accompanied by shortened response and recovery times of 10 and 29 s, respectively. Moreover, this doping level demonstrates excellent selectivity, reproducibility and long-term stability. The enhancement of gas-sensing performance is elucidated through the electron depletion layer theory and the increase in oxygen vacancies. Additionally, first-principles density functional theory (DFT) calculation was employed to deeply analyze the adsorption behavior of the MoO3 towards TEA before and after doping. This study provides valuable insights into the development of high-performance TEA sensors.