Highly selective adsorption of SO2 on WX2 (X = S, Se, Te) monolayers and the effect of strain engineering: a DFT study

A model of the SO2 molecule is first established, then its adsorption on various monolayers is studied by using a first-principles method. The calculation results show that intrinsic WX2 (X = S, Se, Te) exhibits weak adsorption of SO2, corresponding to a physical adsorption mechanism. The adsorption of SO2 on the WX2 systems doped with As and Ge is calculated and compared based on the first-principles method, revealing that the doped WX2 materials exhibit stronger adsorption of SO2. The single-doped Ge/WTe2 shows greater stability when adsorbing gas molecules according to the degree of change in the structure, while its adsorption energy, charge density, band structure, and density-of-states diagrams confirm its enhanced adsorption characteristics for SO2 gas.