Enhanced chemical activity and gas sensing performance of silicene nanosheets by noble metal (Au, Ag) decoration: A DFT study

Abstract

Based on density functional theory calculations, NO₂ and SO₂ adsorptions on the Ag- and Au-functionalized silicene nanosheets were theoretically examined to explore the potential of the modified silicene nanosheets as efficient gas sensors. According to band structure analysis, both Ag- and Au-functionalized silicene nanosheets revealed metallic behavior. The results on the NO₂ and SO₂ adsorptions on Ag- and Au-functionalized silicene monolayer indicate that both substrates can strongly adsorb the gas molecules with large adsorption energies. There are large charge accumulation between the Au/Ag and Si atoms, which represents the significant connection between these atoms. The large overlaps of the PDOS spectra of the Au and O atoms represent the covalent nature of bonding between them. These insights suggest that Ag and Au can be appropriate adatoms functionalized on the silicene nanosheets for detecting NO₂ and SO₂ molecules.