| Copper oxides have recently been of widespread interest because copper-based materials are widely used in the manufacturing and chemical industry such as the catalyst development. However, a complete picture of the oxidation process of copper is still far from clear, especially the effect of structural defects present on metal surfaces on the initial oxide formation. This thesis focuses on the understanding of the mechanism of initial-stage oxidation of the stepped copper surfaces.;We use density functional theory and first-principles thermodynamics to optimize oxygen adsorbed on the copper surface forming the surface oxide phase. These oxide phases have different stoichiometry depending on the surface morphology and oxygen surface coverage. Using the VASP (Vienna ab-initio simulation package), the oxygen adsorption on Cu (210) and Cu (511) stepped surfaces are studied in detail and compared to the behavior of oxygen adsorption on Ag (210) and Ag (511).;For the Cu (210) structure, underground oxygen atoms occupy distorted octahedral interstitial sites and form a CuO-like phase. In Cu (511) structure, which shows an open step edges, oxygen adatoms end up in the underground off-center tetrahedral sties which are similar to the Cu2O nucleation center. After relaxation, O adatoms together with Cu atoms form Cu-O-Cu zig-zag chains. The top view of the O-Cu-O chains at Cu (210) step edge are particularly stable, which are closely analogous to those exist in the bulk CuO structure. |
