Hierarchical assembly of urchin-like alpha-iron oxide hollow microspheres and molybdenum disulphide nanosheets for ethanol gas sensing

In this paper, we fabricated a high-performance ethanol sensor using layer-by-layer self-assembled urchin-like alpha-iron oxide (α-Fe₂O₃) hollow microspheres/molybdenum disulphide (MoS₂) nanosheets heterostructure as sensitive materials. The nanostructural, morphological, and compositional properties of the as-prepared α-Fe₂O₃/MoS₂ heterostructure were characterized by X-ray diffraction (XRD), energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS), which confirmed its successful preparation and rationality. The α-Fe₂O₃/MoS₂ nanocomposite sensor shows good selectivity, excellent reproducibility, fast response/recovery time and low detection limit towards ethanol gas at room temperature, which is superior to the single component of α-Fe₂O₃ hollow microspheres and MoS₂ nanosheets. Furthermore, the response of the α-Fe₂O₃/MoS₂ nanocomposite sensor as a function of ethanol gas concentration was also demonstrated. The enhanced ethanol sensing properties of the α-Fe₂O₃/MoS₂ nanocomposite sensor were ascribed to the synergistic effect and heterojunction between the urchin-Like α-Fe₂O₃ hollow microspheres and MoS₂ nanosheets. This work verifies that the hierarchical α-Fe₂O₃/MoS₂ nanoheterostructure is a potential candidate for fabricating room-temperature ethanol gas sensor.