First-principles study of nitrogen and carbon monoxide adsorptions on silicene

Abstract

Atomic adsorptions of N, C and O on silicene and molecular adsorptions of N2 and CO on silicene have been investigated using the density functional theory (DFT) calculations. For the atomic adsorptions, we find that the N atom has the most stable adsorption with a higher adsorption energy of 8.207 eV. For the molecular adsorptions, we find that the N2 molecule undergoes physisorption while the CO molecule undergoes chemisorption, the corresponding adsorption energies for N2 and CO are 0.085 and 0.255 eV, respectively. Therefore, silicene exhibits more reactivity towards the CO adsorption than the N2 adsorption. The differences of charge density and the integrated charge calculations suggest that the charge transfer for CO adsorption ([Formula: see text]0.015[Formula: see text]) is larger than that for N2 adsorption ([Formula: see text]0.005[Formula: see text]). This again supports that CO molecule is more active than N2 molecule when they are adsorbed onto silicene.