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The challenge encountered by the sensor in practical application is that the optimal working temperature is high, which will cause certain dangers in the work. Herein, we fabricated a p-p heterojunction composite LaFeO 3 /YFeO 3 planar electrode sensor for gas detection. The planar electrode sensor adopts the method of direct heating, which reduces the optimal working temperature of the sensor compared with the traditional side-heated alumina ceramic tube sensor. The optimal operating temperature of the LaFeO 3 /YFeO 3 (0.8:0.2) planar electrode sensor is 110 °C. In addition, we also performed multi-wavelength (470, 420, and 370 nm) light illumination experiments on the LaFeO 3 /YFeO 3 sensor to improve gas response. Under 370 nm light illumination, the response values of the LaFeO 3 /YFeO 3 (0.8:0.2) sensor to 30 ppm methanol, acetone, and ethanol were 166.82, 199.58, and 292.67, which were 1.19, 1.33, and 1.36 times than those in the dark. The lowest detection limits of the LaFeO 3 /YFeO 3 (0.8:0.2) sensor under 370 nm light illumination for methanol, acetone, and ethanol were 0.3, 0.8, and 0.2 ppm, respectively. Therefore, the LaFeO 3 /YFeO 3 (0.8:0.2) planar electrode sensor has the advantages of small size, low optimal operating temperature, low power consumption, high response value to volatile organic compounds gases, and high-cost performance for use in different gas environments. • The LaFeO 3 /YFeO 3 (a:b) materials were fabricated by the sol-gel method. • Gas sensor was prepared using 1.5 × 1 mm plane electrodes. • The sensors were tested under multi-wavelength light illumination. • The optimal operating temperature of LaFeO 3 /YFeO 3 (0.8:0.2) sensor was 110 °C. • Light illumination improved the sensor's response to VOCs gases. [ABSTRACT FROM AUTHOR]

Abstract Pd:LaFe 0.9 Mg 0.1 O 3 is researched as a acetone sensor with high response. The response of sensor expose to 10, 20, 50, 100, 200, 500, 1000 ppb is 1.15, 1.24, 1.45, 1.72, 1.98, 2.57 and 3.28 at 180 °C at normal atmospheric pressure, respectively. This sensor can detect extreme low limit of acetone gas as 10 ppb. The response of sensor under light is also measured, the result indicate that the optimum temperature is reduced and the response at this optimum temperature is promoted. The sensor show excellent selectivity to acetone gas among mixed composition. Experiments prove that since its extreme low detecting limit to acetone gas, the sensor can be used to preliminary judge that if person is diabetic. [ABSTRACT FROM AUTHOR]