Enhanced acetone sensing performance of an α-Fe2O3-In2O3 heterostructure nanocomposite sensor

The reasonable design of heterojunction nanostructures is a useful method for enhancing the properties of gas sensors based on metal oxide semiconductors. In this study, α-Fe2O3-In2O3 heterostructure nanocomposites were synthesized via a low-cost and simple hydrothermal route. The structure and morphology of α-Fe2O3-In2O3 heterostructure nanocomposites were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, the Brunauer-Emmett-Teller (BET) approach, and X-ray photoelectron spectroscopy. The results showed that the diameter of the α-Fe2O3-In2O3 heterostructure nanocomposites was about 2-3 μm, and the length and diameter of the Fe2O3 nanorods were about 1 μm and 10-15 nm, respectively. The BET surface area was calculated as 67.23 m2/g and the pore size was mainly distributed around 11 nm. Gas-sensing tests showed that the optimum operating temperature for the as-obtained α-Fe2O3-In2O3 heterostructure nanocomposite-based sensor was 300 °C. When the acetone concentration was 20 ppm, the response of the α-Fe2O3-In2O3 heterostructure nanocomposite-based sensor was about 37, which was about seven times higher than that of the pure material. Therefore, this α-Fe2O3-In2O3 heterostructure nanocomposite system merits further systematic investigation.