Chromium deposition on ordered alumina films: An x-ray photoelectron spectroscopy study of the interaction with oxygen

We have studied metallic and oxidized chromium layers on thin ordered alumina films grown on a NiAl~110! substrate using x-ray photoelectron spectroscopy. The interaction between the chromium layers and the substrate has been characterized after deposition at room temperature and after oxidation at 300 and 700 K. Our results indicate partial oxidation of the deposited chromium with the fraction of oxidized Cr decreasing with increasing Cr coverage. Oxidation of the chromium layers at room temperature using O2 results in Cr 31 species on the surface. These oxidized chromium species can be reduced by heating the sample to 700 K for 5 minutes. Oxidation at 700 K results in chromium species that cannot be thermally reduced. Our results do not indicate formation of Cr species although such are present in impregnated catalysts. © 2002 American Institute of Physics. @DOI: 10.1063/1.1434954#