X-ray electron spectroscopy applied to the valency states of platinum and tungsten in a type L metal-bearing zeolite

Abstract

This paper discusses the study of the electron interaction between Pt and W in type L zeolite. The modifying element is added to the platinum-bearing zeolite to produce reforming catalysts of a new type for use in petrochemical synthesis, information of some practical value as well as of scientific interest. From the research it appears that Pt and W in KL zeolite form not only metal-cluster structures but also ions, and possibly also mixed formations involving W /sup n+/ ions and Pt atoms, which show neutral and electron-deficient features. The valency states of the deposited W and Pt, which lie at the edge of the valence band for the carrier, are partially displaced into the forbidden band. Electron pumping alters the impuritylevel structure, which also indicates a cluster character for the deposited metals.