MoSe-Layered Nanosheet Decorated SnO Hollow Nanofiber-Based Highly Sensitive and Selective Room Temperature HS Gas Sensor.

In this work, we successfully demonstrated a MoSe@SnO nanocomposite-based room temperature HS 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 MoSe-layered nanosheets and SnO-hollow nanofiber result in a high surface area for HS gas adsorption. On exposure to calcination, the electro-spun PVP/SnO 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 HS gas. The MoSe@SnO 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 HS interactions. The sensor proves an excellent sensitivity toward HS 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 HS gas in contrast to other gases as well as stability and longevity over time.