Highly sensitive ethanol and acetone gas sensors with reduced working temperature based on Sr-doped BiFeO3 nanomaterial

An effective method to prolong the use time and long-term stability of gas sensors is by lowering the working temperature. However, reducing the working temperature and increasing the sensitivity of a gas sensor is essential to enhance gas-sensing performance. In this work, Sr-doped ferrite bismuth nanomaterial has been synthesized by the facile sol–gel method and their surface morphology, microstructure, and surface chemical composition were characterized. Sr-doped ferrite bismuth is a single-phase nanomaterial with about 50 nm average grain size and rhombohedral crystal structure (Space Group R 3c). The gas-sensing results show that Sr dopant can significantly enhance the sensitivity and reduce the working temperature. Furthermore, the optimum working temperature of Sr-doped BiFeO3 sensor reduces from 244 °C to 208 °C. At the optimum working temperature (208 °C), Sr-doped BiFeO3 gas sensor's sensitivities to 200 ppm ethanol and acetone are nearly the same value (49.5), which are respectively 1.3 and 1.4 times more than BiFeO3 gas sensor at 244 °C. A related gas-sensing mechanism is also discussed.