Oxygen adsorption on an alkali metal-covered Ni(100) surface
1981; Elsevier BV; Volume: 104; Issue: 1 Linguagem: Inglês
10.1016/0039-6028(81)90133-3
ISSN1879-2758
AutoresМ. Кискинова, L. Surnev, G Bliznakov,
Tópico(s)Catalytic Processes in Materials Science
ResumoThe oxygen chemisorption on an alkali (Na, K, Cs) covered Ni(100) surface and its initial oxidation were studied by Auger and electron energy loss spectroscopy (ELS). It was found that in the presence of an alkali metal, the sticking coefficient S remains unity up to a given oxygen coverage of θOcwhose value depends on the alkali overlayer concentration and the ionicity of the Ni-alkali metal bond. At a given oxygen coverage, the line shapes of Auger and loss spectra are almost the same for alkali-covered and clean Ni(100), which suggests that alkali metals cause no change in the character of the Ni-O bond. The effect of alkali metals is associated with increasing electron charge in the surface region, which facilitates oxygen chemisorption. The enhanced surface oxygen concentration in the presence of an alkali metal results in the formation of an oxide phase at lower oxygen exposures than is the case of clean Ni surfaces.
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