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

alpha-MoO3/alpha-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 alpha-Fe2O3 nanorods grew on the surface of alpha-MoO3 nanobelts. The result shows the length and the width of alpha-MoO3 nanobelts to be about 6 mm and 200 nm. The average length of an alpha-Fe2O3 nanorod was 10 nm. The sensing properties towards various kinds of gases were tested and the heater-type gas sensors based on alpha-MoO3 nanobelts and alpha-MoO3/alpha-Fe2O3 nanostructure composites showed excellent performance towards xylene. It was found that such heterostructure composites exhibited enhanced xylene sensing properties compared with alpha-MoO3 nanobelts. For example, at a xylene concentration of 5 ppm, the response of the alpha-MoO3/alpha-Fe2O3 composites was 4.79, which was about 3 times higher than that of alpha-MoO3 nanostructures at 206 degrees C.