The role of surface oxygen vacancy in N2O decomposition on Cu2O(111) surface:: A DFT study

The role of a surface oxygen vacancy in the N2O dissociation over a Cu2O surface was studied using density functional theory-generalized gradient approximation periodic calculations. To perform this study, surface slab model-Cu2O(111)-(root 3 x root 3) R30 degrees surface cell was used. The results indicated that N2O adsorption properties were associated with the surface oxygen vacancies. The presence of a surface oxygen vacancy, prepared by removing one O-SUF atom from (root 3 x root 3) R30 degrees supercell, makes the N2O decomposition possible, which was believed to occur at a oxygen vacancy site. The N2O decomposition at the surface oxygen vacant site depends on whether the molecule is adsorbed with the O- or N-end on a vacancy. For the first case, the reaction proceeds spontaneously, which leads to an ejection of N-2 from the surface and the rest of the oxygen atoms occupying the vacancy. In the second case, even though there is an elongation of both N-N and N-O bonds, the dissociation is unfeasible due to very small adsorption energy and high activation energy. The role of the defective surface with surface oxygen vacancy is to provide electrons to the adsorbed molecule.