Highly selective adsorption on monolayer MoS2 doped with Pt, Ag, Au and Pd and effect of strain engineering: A DFT study

The adsorption of CO2, SO2 and NO2 gas molecules on X (Pt, Ag, Au and Pd)-doped monolayer MoS2 is studied in terms of adsorption energies, charge transfer, band structures, and charge density differences by density functional theory (DFT). In this study, monolayer MoS2 systems respectively doped X (Pt, Ag, Au and Pd) all have extremely high formation energies, in which the strong interactions between the dopant atoms and the S vacancy of monolayer MoS2, resulting that dopant systems were greatly stable. Compared with pure monolayer MoS2, metal X (Pt, Ag, Au and Pd)-doped MoS2 has stronger adsorption performance and electrical conductivity in adsorbing gas molecule, which mainly caused by the new characteristic peaks near the Fermi level after adsorption that promote the migration of electrons from the adsorbent to the matrix, thereby enhancing the adsorption. The system doped metal has the best adsorption effect on SO2 (adsorption energy is -2.806 eV) and NO2 (adsorption energy is -2.539 eV), which is mainly related to relatively powerful electron transfer ability. The results show that the Pt-doped monolayer MoS2 and Au-doped monolayer MoS2 can effectively improve the adsorption capacity of SO2 and NO2 gas molecule increasing the application potential for absorption of polluted gas.