CO2 sensing properties and mechanism of nanocrystalline LaFeO3 sensor

LaFeO3 nanocrystalline powders prepared by sol-gel method with annealing at 800 degrees 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 degrees 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. (C) 2013 Elsevier B.V. All rights reserved.