Anchoring Fe2O3 nanosheets on NiO nanoprisms to regulate the electronic properties for improved n-butanol detection

Metal oxide heterostructures have great potential in gas sensor devices due to the attractive chemical and electronic properties at the heterogeneous interfaces. Herein, a unique heterostructure of NiO nanoprisms/Fe2O3 nanosheets is rationally designed by a solution method for use in n-butanol sensors with superior performances. Mott-Schottky tests reveal that the conductivity of the NiO sensor transforms from p-type to n-type after growing Fe2O3. This conversion of conductivity plays a crucial role in improving the sensor response, which overcomes the low response of p-type metal oxides. The sensor shows good linear response within the concentration range of 0.1–20 ppm n-butanol under operating temperatures (Room Temperature-320 °C). Gas sensing investigations show the sensor based on NiO/Fe2O3 has a response of 4.2–10 ppm n-butanol at an optimal temperature of 200 °C, revealing a 3-time enhancement compared to pure NiO. Meanwhile the NiO/Fe2O3 sensor exhibits a detection limit of 48 ppb, which is much lower than that (296 ppb) of NiO. The proposed structural design in this work provides a new idea for synthesis of high-performance sensing materials for the detection of ppb-level n-butanol.