Two Different States of Copper Ions in Zeolites

Abstract

This work is devoted to the study of copper ion positions in zeolite matrices. Copper cations were exchanged in mordenite and zeolite X from aqueous solutions of different copper salts varying their concentrations. Electronic state of copper in ion-exchanged samples exchanged and dried at different temperatures was evaluated by XPS spectroscopy. Depending on conditions of exchange treatment copper was found to be distributed between two different accessible sites in zeolites. These copper ions are stabilized as isolated species with well-defined oxygen coordination polyhedra.