This study examines the adsorption mechanisms of ethanol, propanal, butanone, and benzene, which represent four typical functional groups-alcohol, aldehyde, ketone, and aromatic-on the monolayer WS2 surface using the non-local van der Waals density functional theory. The results indicate that all four gases exhibit physical adsorption on the WS₂ surface. The adsorption is primarily governed by van der Waals interactions between the gas molecules and the WS₂ substrate. Among the studied gases, butanone demonstrates the highest charge transfer (0.36 e) due to the strong polarity of the ketone functional group (-C = O). This significant charge transfer not only enhances the interaction between the gas and the WS₂ substrate but also improves the sensor’s sensitivity by inducing pronounced changes in the electronic properties of WS₂. Benzene, an aromatic compound, exhibits the highest adsorption energy (637 meV), reflecting the strong π-π interactions between its aromatic ring and the WS₂ surface. This makes benzene the most stable adsorbate among the gases studied, highlighting its potential for detecting aromatic compounds in sensor applications. The results could provide new prospects for the use of WS2 in high-performance sensing devices.
