The dissociative adsorption of H2 on Cu(100): orientation dependence and impurity effects

Abstract

The dissociative adsorption of H2 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 H2 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 H2 dissociation by lowering the activation barrier height; Ag, however, impedes the H2 dissociation since the activation barrier is lifted. Various H2 dissociation pathways are discussed and the corresponding potential-energy surfaces (PESs) are presented.