Abstract
Mössbauer characterization of iron catalysts following Fischer-Tropsch reaction at 523 °K reveals significant differences in carbide phases formed depending on particle, support, and alloying with Ni. Small iron particles on silica favor formation of the unstable ε{lunate}′ and ε{lunate} carbides. Large iron particles on silica and small particles on magnesia form χ carbide as is normal for bulk unpromoted iron. Alloying iron with nickel in approximately equimolar amounts completely prevents formation of bulk carbides at our reaction conditions, but some evidence exists for formation of surface carbon. The complexity of the metastable Fe/FexC/C system is further exemplified in a series of spectra recorded at intermediate reaction times. These data demonstrate time dependency of carbide phases formed and dependence of the rate of carbide formation on average metal particle size.
Original language | English (US) |
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Pages (from-to) | 348-360 |
Number of pages | 13 |
Journal | Journal of Catalysis |
Volume | 58 |
Issue number | 3 |
DOIs | |
State | Published - Jul 1979 |
Externally published | Yes |
ASJC Scopus subject areas
- Catalysis
- Physical and Theoretical Chemistry