Effects of Pt and Au adsorption on the gas sensing performance of SnS2 monolayers: A DFT study

Abstract

In the framework of density functional theory approach, we have reported on the results of the adsorption of some small gas molecules on the Au- and Pt-adsorbed SnS2 monolayers. The changes in the electronic properties of SnS2 monolayers were evaluated upon introducing Pt and Au adatoms. For this purpose, we firstly assessed the atomic configurations, and electronic properties of Pt–SnS2 and Au–SnS2 systems, and then surveyed the gas molecules (COx, NOx, NH3) interaction with Pt–SnS2 and Au–SnS2 systems. The van der Waals (vdW) interactions were included to obtain the most stable geometrical structures of Pt- and Au-functionalized SnS2 monolayers with adsorbed gas molecules. By comparing the adsorption energies of Pt–SnS2 and Au–SnS2 systems towards gas detection with those of perfect ones, we found that the process is energetically stable on the Pt- and Au-adsorbed systems. The charge density difference plots also showed that the electronic properties of Pt- and Au-adsorbed SnS2 systems were influenced by gas adsorption. Our results demonstrated that the considered gas molecules were strongly chemisorbed on the Pt–SnS2 and Au–SnS2 systems, implying the potential of these metal embedded systems in the applications of sensing device for COx, NOx, and NH3 detection.