Sensing behavior and mechanism of La2CuO4–SnO2 gas sensors

The preparation of SnO2 and La2CuO4 powders, and the manufacture of La2CuO4–SnO2 gas sensors are described in some details. The molar ratio of LaCuO4 to SnO2 was chosen as 1:10 (sample 1), 1:8 (sample 2), 1:4 (sample 3), and 2:1 (sample 4), respectively. All samples were measured in the temperature range 20–300°C and under different concentrations of alcohol vapor, H2, and H2S, respectively. The results show that the resistance of La2CuO4–SnO2 sample increases with an increase of La2CuO4 content at given temperature when the La2CuO4 content in sample is lower than 50 mol%. Except sample 4, samples 1, 2, and 3 are sensitive to alcohol vapor, H2, and H2S. As compared with CuO–SnO2 sensor, sample 1 has faster response property and lower operating temperature in the case of same H2S–air mixture concentration.