Facile synthesis of bismuth ferrite nanoparticles for ppm-level isopropanol gas sensor

Breath gas detection has attracted significant attention for the early screening of lung cancer. In this paper, we synthesized bismuth ferrite (BiFeO 3 ) nanoparticles via a green and facile microwave hydrothermal method for detecting low concentration isopropanol. The influence of material’s synthesis process parameters, including temperature, time and power of synthesis on the physicochemical properties, has been explored. The structure, morphology and other material properties of BiFeO 3 were analyzed by a series of characterization methods such as scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray electron spectroscopy (XPS). The effects of synthesis process parameters and testing conditions on gas sensing performance were investigated by a four-channel testing chamber. In addition, the mechanism of gas-sensitive response was also discussed. Considering the authentic situation of exhaled breath of human, we conducted the experiment of ultralow concentration and high humidity systematically. Typically, the BiFeO 3 gas sensor revealed extraordinary sensitive performance at an optimal working temperature of 275 °C. An excellent linear relationship existed in the response and gas concentration, as the response value can reach 3.9 towards 1 ppm isopropanol even if it is in a 100% relative humidity (RH) atmosphere.