High Performance\nH<sub>2</sub>S Sensor Based on Ordered\nFe<sub>2</sub>O<sub>3</sub>/Ti<sub>3</sub>C<sub>2</sub> Nanostructure\nat Room Temperature

The utilization of a heterogeneous nanojunction design\nhas shown\nsignificant enhancements in the gas sensing capabilities of traditional\nmetal oxide gas sensors. In this study, a novel room temperature H<sub>2</sub>S gas sensor employing Fe<sub>2</sub>O<sub>3</sub> functionalized\nTi<sub>3</sub>C<sub>2</sub> MXene as the sensing material has been\ndeveloped. This sensor exhibits a broad detection range (0.01–500\nppm), low detection limit (10 ppb), and rapid response/recovery times\n(10 s/15 s), making it ideal for ppb-level H<sub>2</sub>S detection.\nThe exceptional gas sensitivity of Fe<sub>2</sub>O<sub>3</sub>/Ti<sub>3</sub>C<sub>2</sub> composite to H<sub>2</sub>S can be attributed\nto several key factors. First, the unique layered frame structure\nof Fe<sub>2</sub>O<sub>3</sub>/Ti<sub>3</sub>C<sub>2</sub> significantly\namplifies the surface area of the hybrid material, enhancing the absorption\nand diffusion capabilities of H<sub>2</sub>S molecules. Second, the\nabundance of functional groups (–O, –OH, and –F)\non the surface of Ti<sub>3</sub>C<sub>2</sub> MXene nanosheets provides\nadditional active sites for H<sub>2</sub>S adsorption, The density\nfunctional theory calculation confirms that the adsorption energy\nof the Fe<sub>2</sub>O<sub>3</sub>/Ti<sub>3</sub>C<sub>2</sub> composite\nfor H<sub>2</sub>S (−2.93 eV) is significantly lower than that\nof pure Fe<sub>2</sub>O<sub>3</sub> (−2.37 eV) and Ti<sub>3</sub>C<sub>2</sub> (−0.2 eV). Lastly, the remarkable metal conductivity\nof Ti<sub>3</sub>C<sub>2</sub> MXene ensures efficient electron transfer,\nthereby enhancing overall sensing performance.