Characterization and Catalytic Activity of Y Zeolite Coexchanged with Iron and a Second Polyvalent Cation

L. APARICIO; M. A. ULLA; W. MILLMAN; J. DUMESIC

JOURNAL OF CATALYSIS

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 1988 vol. 110 p. 330 - 347

0021-9517

Y-zeolites exchanged with both Fe and either Ca, La, Eu, Cr, Mn, Co, Ni, or Cu were characterized by magnetic susceptibility measurements and Mössbauer spectroscopy. In addition, these zeolites were studied as catalysts for the oxidation of CO with NO and for the decomposition of N2O into N2 and O2. The results showed that Ca, La, and Eu cations in FeCaY, FeLaY, and FeEuY occupy primarily site I, forcing a large fraction of Fe cations to sites I′, II, and/or II′. Such zeolites exhibited higher reaction rates than FeY for both reactions. Coexchanged, first-row transition metals had a different effect on the Fe. For example, Mn, Ni, and Cu cations in FeMnY, FeNiY, and FeCuY were found to make the Fe more oxidizable and less reducible. Reaction rates measured over CrY, MnY, FeY, CoY, NiY, and CuY showed that the oxidizability of these cations decreases in the order Cr(III) > Fe(II), Cu(I) > Co(II) > Mn(II), Ni(II). Finally, the Fe in FeEuY was found to enhance the reducibility of the Eu.