A fast response & recovery acetone gas sensor based on BiFeO3 nanomaterials with high sensitivity and low detection limit

Abstract

In present work, BiFeO3 was synthesized at different temperatures (450, 500, 550 °C) by tartaric acid sol–gel method. XRD, SEM and TEM were used to characterize microstructure and morphology of as-prepared BiFeO3. All results indicate that as-prepared BiFeO3 is the nanocrystal with single rhombohedrally distorted perovskite structure with the space group R3c and has irregular shapes and the average grain sizes between 50 and 120 nm. BiFeO3 nanomaterials have a low working temperature of 240 °C and high acetone gas response. Especially for BiFeO3 grown at 500 °C, the sensitivity to 50 ppm acetone is about as high as 30 at 240 °C. The response and recovery time of BiFeO3 sensors is respectively about 5 and 18 s. Moreover, BiFeO3 sensors have a low detection limit and the logarithmic curves of the sensitivity and concentration of BiFeO3 sensors satisfy the linear relationship in the low detection range. These results demonstrate that BiFeO3 can be used as an ideal candidate to fabricate high response acetone sensor. Gas sensing mechanism of BiFeO3 is also discussed on the basis of adsorption and desorption of reducing acetone gas and the reaction with oxygen species on the surface of BiFeO3 nanomaterials. This work can give rise to an interesting choice for researching excellent gas sensing properties of other nonstoichiometric oxides.