High Performance H₂S Sensor Based on Ordered Fe₂O₃/Ti₃C₂ Nanostructure at Room Temperature

Abstract

The utilization of a heterogeneous nanojunction design has shown significant enhancements in the gas sensing capabilities of traditional metal oxide gas sensors. In this study, a novel room temperature H₂S gas sensor employing Fe₂O₃ functionalized Ti₃C₂ MXene as the sensing material has been developed. This sensor exhibits a broad detection range (0.01-500 ppm), low detection limit (10 ppb), and rapid response/recovery times (10 s/15 s), making it ideal for ppb-level H₂S detection. The exceptional gas sensitivity of Fe₂O₃/Ti₃C₂ composite to H₂S can be attributed to several key factors. First, the unique layered frame structure of Fe₂O₃/Ti₃C₂ significantly amplifies the surface area of the hybrid material, enhancing the absorption and diffusion capabilities of H₂S molecules. Second, the abundance of functional groups (-O, -OH, and -F) on the surface of Ti₃C₂ MXene nanosheets provides additional active sites for H₂S adsorption, The density functional theory calculation confirms that the adsorption energy of the Fe₂O₃/Ti₃C₂ composite for H₂S (-2.93 eV) is significantly lower than that of pure Fe₂O₃ (-2.37 eV) and Ti₃C₂ (-0.2 eV). Lastly, the remarkable metal conductivity of Ti₃C₂ MXene ensures efficient electron transfer, thereby enhancing overall sensing performance.