Construction of high-performance Fe2O3-In2O3 heterostructure-based hydrogen gas sensor: Experimental and DFT calculation

In this work, Fe₂O₃ nanoparticles were synthesized through a simple hydrothermal method, and a high-performance Fe₂O₃-In₂O₃ heterojunction hydrogen sensor was successfully fabricated via electrospinning. The morphology and elemental composition of the composite material were characterized through scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. A systematic performance test of the sensor was conducted using an experimental testing platform. The optimal doping ratio of Fe₂O₃ was explored, and the sensor's optimal operating temperature was found to be 280°C. At this temperature, the sensor exhibited a response of 32.95–2000 ppm hydrogen, which is 7.6 times higher than that of the pristine In₂O₃, along with rapid response/recovery times (1.5 s/16 s), rosy‌ selectivity, and stability. The improved sensor performance can be primarily ascribed to the creation of the heterojunction and the expanded specific surface area of the materials. The adsorption energy, charge transfer, and other properties of the Fe₂O₃-In₂O₃ composite were calculated using density functional theory, further elucidating the reasons for the improvement in sensor performance.