CO2 sensing properties and mechanism of nanocrystalline LaFeO3 sensor

LaFeO3 nanocrystalline powders prepared by sol–gel method with annealing at 800 °C for 2 h can exhibit considerable sensing response to CO2 gas. The resistance of the LaFeO3 sensor increases with increasing concentration of CO2. At 300 °C, the response of the sensor to 2000 ppm CO2 is 2.19, and its response and recovery times are about 4 and 8 min, respectively. The possible CO2 sensing mechanisms for LaFeO3 sensor are investigated with first principles calculations. Calculated results demonstrate that CO2 could release electrons to the surface of LaFeO3 (0 1 0) pre-adsorbed with high concentration of oxygen, which is consistent with the experimental observation.