Studies of Fluorine in Catalysts with Ultrasoft X-Ray Absorption Spectroscopy

Abstract

The structures of fluorine-doped alumina catalyst powders have been studied by fluorescence yield ultrasoft X-ray absorption spectroscopy. The results presented here demonstrate that important local structural information can be obtained by the technique. It is established that fluoride ions are substituted for oxygen in alumina at low concentration of adsorbed fluorine. For doping levels larger than those required for saturation of the monolayer, we observed AlF3-like features in the radial structure function. These results are in agreement with previous observations of balk AlF3 in aluminas with high levels of fluorine doping. The fluorescence yield method is well suited for determining structures of a wide range of ceramic materials.