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

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.