Xylene gas sensor based on α-MoO3/α-Fe2O3 heterostructure with high response and low operating temperature

Abstract

α-MoO₃/α-Fe₂O₃ nanostructure composites were fabricated via a facile and low-cost hydrothermal strategy. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) were used to characterize the samples. The results revealed that the α-Fe₂O₃ nanorods grew on the surface of α-MoO₃ nanobelts. The result shows the length and the width of α-MoO₃ nanobelts to be about 6 μm and 200 nm. The average length of an α-Fe₂O₃ nanorod was 10 nm. The sensing properties towards various kinds of gases were tested and the heater-type gas sensors based on α-MoO₃ nanobelts and α-MoO₃/α-Fe₂O₃ nanostructure composites showed excellent performance towards xylene. It was found that such heterostructure composites exhibited enhanced xylene sensing properties compared with α-MoO₃ nanobelts. For example, at a xylene concentration of 5 ppm, the response of the α-MoO₃/α-Fe₂O₃ composites was 4.79, which was about 3 times higher than that of α-MoO₃ nanostructures at 206 °C.