Ultrahigh sensitivity acetone sensor based on Gd₂O₃/Fe₂O₃ loose microspheres at low temperature

Pure Fe₂O₃ microspheres and Gd₂O₃/Fe₂O₃ loose microspheres were synthesized successfully by a facile hydrothermal method and followed with calcined. The structure and elemental composition were provided by the X-ray powder diffraction (XRD) and energy-dispersive spectroscopy (EDS). Additionally, the morphology was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), which show the loose surface state of Gd₂O₃/Fe₂O₃ microspheres. Finally, the property of the gas-sensing sensor based on Gd₂O₃/Fe₂O₃ loose microspheres was investigated systematically. It exhibits ultrahigh sensitivity of 268.6 to 100 ppm acetone at low operating temperature 220 °C, which is 9.8 times higher than the pure Fe₂O₃ microspheres sensor (27.5/100 ppm). Remarkably, the response of Gd₂O₃/Fe₂O₃ loose microspheres sensor to 0.1 ppm acetone is 2.3. Furthermore, the sensor shows fast response and recovery time (6/36 s) and splendid selectivity to acetone.