A DFT+u study, including the van der waals interaction, on the adsorption of XO2 molecules on the v2o5(001) surface (x= S, N, O, C)

Abstract

Density functional theory (PBE+U), including the van der Waals interaction, has been used to study the adsorption of four triatomic molecules with two oxygen atoms in the ends, on the V2O5(001) surface. The most stable adsorption configuration for the considered molecules (SO2, NO2, O3 and CO2) is bridge two nearby V–O2 zones via the oxygen atoms regardless the bridge is over the O2 or the O3 and also regardless the van der Waals functional used. The bond between the polar molecules and the surface is via the oxygen atoms of the ends, whereas the bond of the CO2 molecule is via the carbon atom to an O2 or O3. Upon adsorption, there is an accumulation of a very small amount of negative charge near the adsorbate, coming from the upper part of the surface. The interactions are weak and the oxygen atoms of the molecules are about 3 Å from the vanadium ions. The attractive interaction between the adsorbed molecule and the surface is mainly due to the van der Waals interaction regardless the functional used (DFT-D2, optPBE and rPW86).