Possibility of gallium sulfide nanoflakes for detection and adsorption of O2 and H2O: A DFT and thermodynamic perspective

In this study, environmental oxygen and water interaction-driven electronic and thermodynamic properties of pristine and hydrogenated gallium sulfide nanoflakes (GaS-NF) in armchair (AC) and zigzag (ZZ) configurations have been reported. The hydrogenation increases the interaction between GaS nanoflakes, particularly in the zigzag (ZZ) configuration, and the molecules, suggesting enhanced electronic sensitivity in hydrogenated nanoflakes. The ZZ configuration, particularly in the hydrogenated state, shows pronounced reactivity with O₂, maintaining physisorption, as evidenced by the appearance of a prominent O(2p) peak in the density of states analysis. The oxygen interaction increases the quantum capacitance value up to 250 μF/cm² and 200 μF/cm² in zigzag pristine and hydrogenated nanoflake, respectively. Scanning tunneling microscopy (STM) reveals more pronounced electronic localization at the edges. Thermodynamic analysis indicates high adsorption probabilities for both O₂ and H₂O at low temperatures and pressures, with the ZZ configuration being suitable for oxygen detection and the AC configuration for humidity sensing and water filtration applications.