Associated and single iron ions in ion-exchanged Faujasite zeolites

Abstract

Different forms of extraframework ions present in faujasite zeolite prepared by Fe³⁺ ion exchange at different pH values and with subsequent reduction in hydrogen have been studied. "Low-coordination" Fetetr Fe²⁺ ions can be found either in the form of single ions accessible for chemisorption, or in the form of ion associations from which centers of the catalytic processes can be formed in the CO+H₂ reaction. "High-coordination" Fe_oct²⁺ ions are not affected either by chemisorption or by CO+H₂ treatment.