Synthesis and gas sensing properties of α-Fe₂O₃@ZnO core–shell nanospindles

α-Fe₂O₃@ZnO core–shell nanospindles were synthesized via a two-step hydrothermal approach, and characterized by means of SEM/TEM/XRD/XPS. The ZnO shell coated on the nanospindles has a thickness of 10–15 nm. Considering that both α-Fe₂O₃ and ZnO are good sensing materials, we have investigated the gas sensing performances of the core–shell nanocomposite using ethanol as the main probe gas. It is interesting to find that the gas sensor properties of the core–shell nanospindles are significantly enhanced compared with pristine α-Fe₂O₃. The enhanced sensor properties are attributed to the unique core–shell nanostructure. The detailed sensing mechanism is discussed with respect to the energy band structure and the electron depletion theory. The core–shell nanostructure reported in this work provides a new path to fabricate highly sensitive materials for gas sensing applications.