The dissociative adsorption of H2on Cu(100): orientation dependence and impurity effects

The dissociative adsorption of H 2 On Cu(100) is studied by using the embedded-atom method (EAM). The molecular orientation dependence and the impurity effects have been investigated. It is found that the most favourable molecular orientation for H 2 dissociation is to keep the H-H axis parallel to the surface. In this case, the corresponding activation barrier is lowest. Calculations show that when an impurity atom is present in the Cu substrate, the chemisorption properties near the impurity atom are affected. Ni and Pd can promote the H 2 dissociation by lowering the activation barrier height; Ag, however, impedes the H 2 dissociation since the activation barrier is lifted. Various H 2 dissociation pathways are discussed and the corresponding potential-energy surfaces (PESs) are presented.