C-doped LaFeO3 Porous Nanostructures for Highly Selective Detection of Formaldehyde

Abstract

LaFeO3 is a promising sensing material owing to its preferable stability and lower phase formation temperature, while the sensing detection limit, working temperature and selectivity are far from the requirement of practical application. Herein, porous LaFeO3/C nanocomposites were successfully synthesized for the first time through a facile foaming sol-gel technique. The amount of carbon and the microstructure of nanocomposites can be simply controlled by adjusting the content of PVP in precursors. The systematical sensing investigation demonstrates that LaFeO3 with 10 % PVP exhibits excellent sensing properties with sensitivity of 74.3–50 ppm formaldehyde at 125 °C, which is around 3 times higher than that of pristine LaFeO3. When the formaldehyde concentration is as low as 500 ppb, the sample still presents a high response value of 2. Moreover, the sample shows good long term reliability and high selectivity of 13.3 to formaldehyde. Further detailed analysis indicates the improving sensing performance of LaFeO3/C can be attributed to the large specific surface area, porous structure and increased electrical conductivity of the material. This work builds an efficient and simple example for the fabrication of high sensing performance formaldehyde sensors.