Theoretical study on water adsorption and dissociation on the nickel surfaces.

Abstract

Using density functional theory methods, H2O dissociation was investigated on the Ni(111), Ni(100), and Ni(110) surfaces. H and O atom as well as OH species adsorb stably at the high coordination sites. While on the Ni(110) surface, the OH species prefers at the twofold short bridge site because the adsorption on the fourfold hollow site is less feasible due to the increased distances between the nickel atoms. The amount of charge transfer is related to the adsorption stability. The more charge transfer, the more stable the adsorption. The charge transfer decreases in the order of O > OH > H. H2O molecule adsorbs at the top site in a configuration parallel to the surface. The final products are different for H2O dissociation due to the different mechanisms. On the Ni(111) surface, the final product is the O atom. On the Ni(100) and Ni(110) surfaces, the most abundant species are OH and H, but the reaction mechanisms were different. It is not necessary to linear BEP relationship for a given reaction on different surfaces. These results could provide fundamental insights into water behaviors and a favorable theoretical basis for further understanding and research on the interaction between water and metal surfaces.