Adsorption of toxic H2S, CO and NO molecules on pristine and transition metal doped α-AsP monolayer by first-principles calculations

Using first-principles calculations based on density functional theory (DFT-D2 method), the adsorption behavior of pristine and transition metal (TM) atoms (Fe, Ni, Pd and Pt) doped α-AsP monolayer for toxic H2S, CO and NO molecules are systematically studied. The results show that TM dopants prefer to substitute As atoms with lower binding energy. TM doping significantly enhances the adsorption ability of the α-AsP monolayer for H2S, CO and NO molecules. Furthermore, there is a significant change in work function (WF) after H2S, CO and NO adsorption, meaning that the TM doped α-AsP monolayer is sensitive to gas molecules. Double NO can be stably adsorbed on the TM doped substrate plane, indicating that they are suitable for reversible sensor applications under practical circumstances. Our calculations can provide theoretical guidance to develop promising novel two dimensional V–V binary AsP-based gas sensors.