MoSe<sub>2</sub>‑Layered\nNanosheet Decorated\nSnO<sub>2</sub> Hollow Nanofiber-Based Highly Sensitive and Selective\nRoom Temperature H<sub>2</sub>S Gas Sensor

In this work, we successfully demonstrated a MoSe<sub>2</sub>@SnO<sub>2</sub> nanocomposite-based room temperature H<sub>2</sub>S gas sensor.\nA sensing mechanism was proposed based on experimental results and\ndensity functional theory calculations. The FESEM micrographs of the\nheterostructure formed by hydrothermally grown MoSe<sub>2</sub>-layered\nnanosheets and SnO<sub>2</sub>-hollow nanofiber result in a high surface\narea for H<sub>2</sub>S gas adsorption. On exposure to calcination,\nthe electro-spun PVP/SnO<sub>2</sub> nanofiber undergoes the Kirkendall\nphenomenon, resulting in 94.6 nm thick hollow nanofibers. The combination\nof TMD@SMO shows an abundance of charge transfer, resulting in an\nexcellent response toward H<sub>2</sub>S gas. The MoSe<sub>2</sub>@SnO<sub>2</sub> detects a low concentration of 500 ppb with a relative\nresponse of ∼19.9% at room temperature (RT). The simulation,\nusing density functional theory (DFT), discloses that the adsorption\nenergies ranged from −0.3645 to −0.5193 eV, indicating\n reduced bond lengths and significant H<sub>2</sub>S interactions.\nThe sensor proves an excellent sensitivity toward H<sub>2</sub>S gas,\nranging from 100 ppm to 500 ppb, with a LoD of ∼15 ppb at RT.\nAs the sensor worked at RT with accuracy and reliability, consistent\nperformance was observed upon exposure to various humidity levels,\nmaking it suitable for exhaled breath gas sensors. The sensor, as\ndeveloped, also exhibited a good selectivity toward H<sub>2</sub>S\ngas in contrast to other gases as well as stability and longevity\nover time.