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(0 0 1) 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(0 0 1) surface as a model of defective Cu(0 0 1) surface. On the perfect Cu(0 0 1) surface, our GGA-PBE results show that the N2O molecule adsorbs very weakly onto the Cu(0 0 1) 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(0 0 1) 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).