XPS study of complex species intercalated in layered inorganic ion-exchangers, before and after their use as catalysts.

Abstract

The first results of an XPS investigation of layered zirconium phosphate phases intercalated with aromatic diamines or their complexes with transition metal ions are reported. The technique permits the observation that the N-protonation of the hydrated or anhydrous diamine intercalation compounds occurs to a different extent. For complex containing phases, the simultaneous presence of protonated, unprotonated and coordinated nitrogen atoms accounts for a certain degree of dishomogeneity in the materials, probably due to the slow metal ion diffusion between the layers. The XPS spectra of the compounds used as catalysts (Pd-Cu bipyridyl zirconium phosphates) account for the high or low activity observed during the catalytic reactions, and also suggest the probable reaction mechanism of the materials in the catalytic process. © 1989.