Fabrication of NiO Nanosheet/NiFe₂O₄ Nanoparticle Sensor through One-Step Hydrothermal Method for Acetone Detection

Developing high-performance, low-temperature heterostructure gas sensors via simple, rapid methods is a hot research topic in chemical sensors. Here, we report the successful fabrication of NiO/NiFe 2 O 4 nanocomposites via a one-step hydrothermal process. These composites, characterized by their intricate microstructure and morphology, consist of NiO nanoplates interspersed with nanoscale NiFe 2 O 4 particles, forming a distinct heterojunction architecture. The response of NiO/NiFe 2 O 4 heterojunction to acetone gas was measured using a resistance gas sensor. The experimental results show that the response value to 50 ppm acetone at the optimal working temperature (170 °C) is 45. Compared with pure NiFe 2 O 4 , the operating temperature is reduced by 70 °C, and the response value is increased 4.7 times. The sensor exhibited exceptional repeatability, long-term stability, and high selectivity towards acetone. The enhanced gas sensing performance was attributed to the unique morphology of the composites and the synergistic interactions between NiO and NiFe 2 O 4 . The sensing mechanism, involving surface adsorption, charge transfer, and their interplay within the heterojunction, was thoroughly investigated, providing crucial insights for the future development of acetone gas sensors with superior performance.