MoSe₂-Layered Nanosheet Decorated SnO₂ Hollow Nanofiber-Based Highly Sensitive and Selective Room Temperature H₂S Gas Sensor

In this work, we successfully demonstrated a MoSe₂@SnO₂ nanocomposite-based room temperature H₂S gas sensor. A sensing mechanism was proposed based on experimental results and density functional theory calculations. The FESEM micrographs of the heterostructure formed by hydrothermally grown MoSe₂-layered nanosheets and SnO₂-hollow nanofiber result in a high surface area for H₂S gas adsorption. On exposure to calcination, the electro-spun PVP/SnO₂ nanofiber undergoes the Kirkendall phenomenon, resulting in 94.6 nm thick hollow nanofibers. The combination of TMD@SMO shows an abundance of charge transfer, resulting in an excellent response toward H₂S gas. The MoSe₂@SnO₂ detects a low concentration of 500 ppb with a relative response of ∼19.9% at room temperature (RT). The simulation, using density functional theory (DFT), discloses that the adsorption energies ranged from -0.3645 to -0.5193 eV, indicating reduced bond lengths and significant H₂S interactions. The sensor proves an excellent sensitivity toward H₂S gas, ranging from 100 ppm to 500 ppb, with a LoD of ∼15 ppb at RT. As the sensor worked at RT with accuracy and reliability, consistent performance was observed upon exposure to various humidity levels, making it suitable for exhaled breath gas sensors. The sensor, as developed, also exhibited a good selectivity toward H₂S gas in contrast to other gases as well as stability and longevity over time.