ADSORPTION AND DECOMPOSITION OF NITROGEN OXIDES ON Al(111) SURFACE: A DENSITY FUNCTIONAL THEORY STUDY

The interaction and adsorption of NOx(x=1,2) gas molecules on the Al(111) surface were investigated by the density functional theory (DFT) method. The adsorption structures, energies, charge transfer, and density of states (DOS) of the adsorbed NO, NO2 on the Al(111) were studied. The O, O '-bridge NO2* and the N, O-hcp NO* configurations are the most stable configurations of all the adsorption structures. The Bader charge analysis indicates that both NO2 and NO adsorption are accompanied by a back-donation from the top layer Al atoms to the adsorbates. The DOS of the adsorption structures shows that the pi orbitals (NO2) and the pi orbitals (NO) are available for accepting electron density. All these suggest that a strong interaction exists between the Al surface and the NOx(x=1,2). Furthermore, NO2 decomposes into NO and O with the further dissociating into N and O on Al(111), which is thermodynamic favorable and kinetics feasible.