The application of X-ray photoelectron spectroscopy for determining the chemical state of supported catalysts is discussed with particular reference to the system iron-praseodymium-alumina. The XPS studies are complicated by the variable valency, intermediate stoichiometrics and by the variety of structure possibilities in the iron-praseodymium-alumina system. Techniques to cope with differential charging of the sample are described and results presented for the surface characterization of hydrogen conditioned catalysts. Extensive reaction between the catalyst components is shown to occur. It is shown that praseodymium is incorporated in the alumina support and that the reaction of iron at this surface can be distinguished from the reaction in the unpromoted iron-alumina catalyst.
KeywordsMethane Dioxide Microwave Argon Hydroxide
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