Nickel and nickel based alloys are commonly used as metal surfaces in heterogeneous catalysts and in industrial applications. In industry, nickel metal alloys are used as the building material for various components in power plants because of their corrosion-resistant properties. In catalysis, nickel alloy surfaces are studied for applications such as the steam reforming of methane and the oxidation of hydrocarbon fuels in solid-oxide fuel cells. However, carbon deposition on the surface leads to coking and deactivation of the nickel catalyst while oxygen adsorption on the surface leads to the formation of a metal oxide which changes the chemistry of the surface. In order to make new nickel based alloys, it is therefore essential to understand the fundamental interactions of C, O, and CO species with the surface.<br/>Here density functional theory is used to analyze the interactions of C, O, and CO with the (100) and (111) facets of different nickel surface alloys. These interactions are discussed and compared to the pure nickel surface. For the nickel surface alloys, one surface Ni atom is substituted with the alloying atom to represent the surface alloy. Alloying elements include Al, Co, Cr, Cu, Fe, Mn, Mo, Nb, Ti, V, and W. The binding energies of each C, O, and CO on all twelve surfaces have been studied and reaction energies for the dissociation of CO into C and O have been calculated. The density of states for each nickel surface alloy has also been calculated, and the d-band center is compared to the binding energies of C, O, and CO on the surface.<br/>The addition of any of the alloying atoms to the Ni(100) facet has a destabilizing effect on the adsorption of C, O, and CO compared to the adsorption on the pure nickel surface. In contrast, on the (111) facet the addition of an alloying atom increases the stability of the adsorbates on the surface compared to the pure nickel surface. Overall, nickel surface alloys with Co, Cu, or Fe exhibit the weakest interactions between the surface and the C, O, and CO adsorbates while the nickel surfaces alloyed with Mo, W, V, or Ti induce the strongest binding of the adsorbates on the surface.

Density functional theory study of the interactions of C, O, and CO with nickel surface alloys

253rd National Meeting (2017)

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