Room-temperature solid state synthesis of ZnO/α-Fe ₂O ₃ hierarchical nanostructures and their enhanced gas-sensing properties

A facile solid state reaction route was employed to synthesize the ZnO/α-Fe ₂O ₃ hierarchical nanostructures by grinding zinc acetate, α-Fe ₂O ₃ and sodium hydroxide with proper molar ratios together at room temperatures without any surfactant and template. Their morphological feature was characterized as self-assembled by nanosheets on which α-Fe ₂O ₃ nanoparticles were well sprinkled, and it was observed that the amount of α-Fe ₂O ₃ added significantly affected the overall morphology. Furthermore, gas-sensing properties of the obtained products were studied. The results demonstrated that the sensors based on ZnO/α-Fe ₂O ₃ hierarchical nanostructures exhibited a much higher sensitivity to ethanol vapor than the sensors based on pure ZnO nanostructures and the 2% α-Fe ₂O ₃-added ZnO/α-Fe ₂O ₃ nanostructures sensors showed the highest sensitivity. Additionally, the mechanism of gas sensing was also studied.