Construction of Hierarchical α-Fe₂O₃/SnO₂ Nanoball Arrays with Superior Acetone Sensing Performance

Gas sensors based on SnO₂, Fe₂O₃, and their nanocomposites are promising candidates for sensing of acetone, ethanol, hydrogen, NO₂, ozone, and formaldehyde. In this work, a rational hydrothermal route is designed to prepare α-Fe₂O₃/SnO₂ porous sphere arrays assembled with hierarchical nanostructure (denoted as α-Fe₂O₃(x%)/SnO₂). The results demonstrate that the α-Fe₂O₃(4%)/SnO₂ based sensor exhibits excellent sensing performance, the short response/recovery time of 3 and 4 s, respectively. A very low working temperature of 200 °C, wide linear detection range (from 500 ppb to 500 ppm), and long-term cycling stability of as long as 90 days, and stable performance at 80% of relative humidity. The sensing signals can be accurately sampled and processed by the integrated circuit system, to collect and monitor the acetone concentration alteration signals in real time. Furthermore, the gas sensing performance is interpreted by the functions of hierarchical nanostructure and synergistic effect of Fe₂O₃/SnO₂ nanohybrids.