Carbidic and graphitic carbon on Ni(771): aspects for catalysis

Abstract

Vicinal surfaces are often used to model real catalysts, because they exhibit steps and kinks, which are believed to be catalytically active sites. On Ni(771) - a vacinal Ni(110) surface - major differences between carbidic and graphitic carbon were disclosed, using scanning tunneling microscopy, low-energy electron diffraction and Auger electron spectroscopy: The carbidic phase exhibits a (4×1) superstructure affecting only the inner regions of the Ni(110) terraces. Graphitic carbon, on the contrary, forms a macromolecular surface arrangement that preferentially decorates and thus inactivates the catalytically active step sites. © 1992.