Enhanced CO2 response of La1-xFeO3-δ perovskites with A-site deficiency synthesized by flame spray pyrolysis
Measuring the CO 2 concentration is the base of carbon accounting which aims to abate the greenhouse gas emission. This paper pays attention to developing sensitive material for CO 2 detection in vehicle exhaust. For this purpose, La 1-x FeO 3-δ nanoparticles with A-site deficiency were synthesized by flame spray pyrolysis (FSP). The dynamic response of the prototype CO 2 sensors was evaluated by checking the gas-mixture with 5%–15% CO 2 . It was observed that the amount of A-site deficiency would obviously affect the performance of the material. La 0.95 FeO 3-δ sensor exhibits the highest response (S = 3.38) and a relatively short response time (t 90 = 114s) among the serial La 1-x FeO 3-δ sensors (x = 0, 0.02, 0.05, 0.07 and 0.1). The improvement of the response might be attributed to the increase of oxygen vacancies and the higher valence of B-site cations caused by the introduction of A-site deficiency. Furthermore, the sensor exhibited good selectivity against NH 3 , NO, NO 2 and CO, as well as good repeatability. However, water vapor is still a disturbance in the response. The response at 40% RH and 80% RH are 2.11 and 1.73, respectively. Finally, the sensing mechanism based on the participation of the oxygen vacancies was discussed.
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