Hydrothermal synthesis of monodisperse α-Fe2O3 hollow microspheroids and their high gas-sensing properties

Y-doped α-Fe2O3 hollow microspheroids were synthesized by one-pot hydrothermal reaction and subsequent annealing at 550 °C for 4 h. The as-synthesized α-Fe2O3 hollow microparticles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and gas-sensing measurement device, and the results showed that the diameters of all these microparticles were around 1.6-2.3 μm. In order to demonstrate the potential application, gas sensors based on as-synthesized monodisperse α-Fe2O3 hollow microspheroids were fabricated. The gas sensing results showed that the response value of 4 wt% Y-doped α-Fe2O3 hollow microspheroids sensor to 200 ppm ethanol was 126.3 at the optimum operating temperature of 260 °C. Finally, the possible formation mechanism of α-Fe2O3 hollow microspheroids and the gas-sensing mechanism of sensors were proposed, too.