Gas Sensing Properties of Alkali Metal Decorated Pristine and Defect Α-Asp Monolayer Toward Acid So2 and Alkaline Nh3 Molecules

Abstract

The sensing properties of Li and Na decorated pristine and defect α -AsP monolayer for acid SO 2 and alkaline NH 3 toxic gas molecules are systematically studied using first-principles calculations based on density functional theory (DFT-D2 method). The results suggest that the alkali metal atoms decorated defect α -AsP monolayer have moderate adsorption energies for SO 2 and NH 3 gas molecules. In addition, a prominent increase in work function (WF) after SO 2 and NH 3 adsorption endow Li and Na decorated pristine and defect α -AsP monolayer with high sensitivity, and there is a clear relationship between the change of WF and the direction of charge transfer. The electronic local function (ELF) and density of states (DOS) calculation results show that the adsorption of SO 2 on these substrates is mainly determined by electrostatic interaction and NH 3 is bound to the substrate by a covalent bond. The optical and thermodynamic analysis demonstrate that the Li and Na decorated pristine α -AsP monolayer may be a promising material for the detection and storage of SO 2 and NH 3 toxic gas molecules. Our calculations can provide practical guidance for the research of promising novel two-dimensional V-V binary AsP-based gas sensors.

Keywords: Arsenic phosphorus, Alkali metal, Gas sensing properties, First-principles calculations