Adsorption of Atoms on Cu Surfaces: A Density Functional Theory Study

The chemisorption of atoms (H, N, S, O, and C) on Cu surfaces has been systematically studied by the density functional theory generalized gradient approximation method with the slab model. Our calculated results indicate that the orders of the adsorption energy are H < N < S < O < C on Cu(111) and H < N < O < S < C on Cu(110) and Cu(100). Furthermore, the adsorption energies of the given atoms on Cu(100) are larger than those on Cu(111) and Cu(110). The preferred adsorption sites are a 3-fold hollow site on Cu(111) and a 4-fold hollow site on Cu(100), but the preferred adsorption sites on Cu(110) are different for different adatoms. The energy, as well as the geometry, is in good agreement with the experimental and other theoretical data. In addition, this study focuses on the electronic and geometric properties of the metal-atom (M-A) bond to explain the difference in adsorption energies among adatoms. A detailed investigation of the density of states curves explains the nature of the most stable site. Finally, we test the effect of the coverage and find that the surface coverage has no influence on the preferred adsorption sites of the given adatoms on Cu(110) with the exception of hydrogen and oxygen, but has much influence on the value of the adsorption energy.