Effect of Cr Doping on the Surface Characteristics of Ni Metal Studied with First-Principles Calculation

The influence of Cr doping on the surface characteristics of Ni metal, including the surface energy, work function, adsorption and dissociation, has been investigated by means of first-principles calculation based on density functional theory. The results reveal that with the increase in Cr doping amount, the surface energies for all (111), (110) and (100) surfaces increase, whereas the work functions of (111) and (100) surfaces decrease followed by an increase and that of (110) surface has been decreasing. On the typical Ni(111) and Ni–Cr(111) surfaces, the adsorption energies follow the sequence O > OH > H > H2O, and the doping of Cr increases the chemical activity of surfaces leading to the improvement of adsorption energies. The H2O dissociating to OH and H is easier than the subsequent OH dissociating to O and H. The addition of Cr into Ni surface decreases the energy barriers and significantly increases the reaction rate constants.