Stability and separation of phases in Pd and Fe exchanged NaX and NaZSM-5 catalysts in Co+H2 reaction

Pd and Fe exchanged NaX and NaZSM-5 catalysts (Pd/Fe=5) were studied. The components formed in the course of hydrogen activation at 720 K and their transformations taking place during treatments in CO+H₂ at 570 and 500 K are described. Pd_xFe, Fe²⁺ ions in octahedral and tetrahedral environments and x-iron carbide components are identified. The bimetallic component is not affected by the CO+H₂ treatment. The Fe²⁺ ions located only in tetrahedral environment were transformed into iron carbide in the X zeolite framework, while the Fe²⁺ ions of octahedral environment were also transformed in part to carbide in the ZSM-5 lattice.