Coverage-dependent adsorption of nitrous oxide (N2O) on perfect and defective Cu(0 0 1) surfaces: A DFT investigation with and without van der Walls forces

Abstract

The adsorption of the harmful nitrous oxide (N2O) on the perfect and defective Cu(001) surfaces was studied using self-consistent periodic density functional theory (DFT) with the GGA-PBE functional and vdW-DF dispersion correction. We have considered Cu adatom on Cu(001) surface as a model of defective Cu(001) surface. On the perfect Cu(001) surface, our GGA-PBE results show that the N2O molecule adsorbs very weakly onto the Cu(001) surface for 0.25 and 0.50 ML coverages, but a desorption is observed at 0.75 and 1.0 ML coverages. The inclusion of the vdW-DF correction increases the adsorption energies relative to values obtained from pure GGA-PBE functional, however, both types of processes, i.e., adsorption and desorption are retained with respect to the coverages. The dissociative adsorption of N2O on the bare Cu(001) surface is energetically preferred to the molecular adsorption, using the GGA-PBE functional. Regarding the defective surface, we note that the presence of a Cu adatom stabilize the adsorption of N2O better than a flat surface using the GGA-PBE functional, while the opposite effect is observed with vdW-DF correction. The electronic structure was analyzed in terms of the projected density of states (PDOS).