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Title: Magnetic, Moessbauer, and catalytic properties of the zeolite catalyst ZSM-5(Fe)

Journal Article · · J. Appl. Phys.; (United States)
DOI:https://doi.org/10.1063/1.330966· OSTI ID:5538317

Iron-impregnated medium pore zeolite ZSM-5 (pore opening of 5.5 A) is an efficient catalyst for the conversion of synthesis gas (CO+H/sub 2/) to high octane gasoline. Activity and selectivity of the ZSM-5 (Fe) depends upon the manner in which Fe is impregnated on ZSM-5. Magnetic and Moessbauer studies were conducted on catalysts prepared by two methods: (a) ferric nitrate impregnation and (b) carbonyl Fe/sub 3/(CO)/sub 12/ impregnation on the zeolite. These studies were conducted for various stages of preparation and after use of the catalysts. The carbonyl impregnated sample in the as-prepared form contained ultrafine ..gamma..-Fe/sub 2/O/sub 3/ of d = 60--66 A, as evidenced by superparamagnetic behavior seen in magnetic and Moessbauer studies. In contrast, the as-prepared, nitrate impregnated sample showed ..cap alpha..-Fe/sub 2/O/sub 3/ of approximate particle size of 100 A. Both samples were reduced to about 80% metallic Fe in flowing H/sub 2/. On exposure to synthesis gas, the carbonyl impregnated sample yielded a substantial amount of Fe/sub 3/O/sub 4/ in addition to chi carbide, wheres the nitrate impregnated sample exhibited epsilon, chi, and theta carbides. The steady catalytic activity and selectivity of the carbonyl impregnated sample can be related to the ultrafine iron dispersions leading to the observed phases in the used catalyst.

Research Organization:
Department of Physics, Pennsylvania State University, McKeesport, Pennsylvania 15132
DOE Contract Number:
AC22-81PC41265
OSTI ID:
5538317
Journal Information:
J. Appl. Phys.; (United States), Vol. 53:3
Country of Publication:
United States
Language:
English