Trimethylamine sensing properties of nano-LaFeO3 prepared using solid-state reaction in the presence of PEG400

LaFeO3 precursors are prepared using solid-state reaction in the presence of PEG400, and then LaFeO3 nano-powders are obtained through heating these precursors under different conditions. Eventually, LaFeO3 thick film sensors are fabricated by using LaFeO3 nano-materials as sensing materials. The phase composition and morphology of particles in these materials are characterized through X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The XRD analysis results reveal that LaFeO3 can be obtained by heating at 400–900 °C. TEM images manifest that the average particle sizes increase with heating temperature increasing, the particle sizes are in the range of 50–80 nm when heating temperature is increased to 800 °C. Furthermore, the influence of the heating duration and the heating temperature on the gas-sensing properties of the sensors based on LaFeO3 nano-materials is also investigated in this work. The sensitivities to several organic gases, such as (CH3)3N and (CH3)2CO are studied. It is found that the sensor based on LaFeO3 nano-material (800 °C, 2 h) exhibits best performance in all sensors investigated in this work. In detail, the sensitivities of the sensor based on LaFeO3 nano-material (800 °C, 2 h) to 1000 and 0.001 ppm (CH3)3N at 208 °C are as high as 2553 and 1.6, respectively; and the response time and recovery time for 10 ppm trimethylamine are 8 and 50 s, respectively.