Dynamic X-ray diffraction study of an unsupported iron catalyst in Fischer-Tropsch synthesis

Journal Article · Wed Apr 01 04:00:00 EST 1992 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(92)90350-Q· OSTI ID:7027332

Jung, H; Thomson, W J ^[1]

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1. Washington State Univ., Pullman (United States)

In situ, Dynamic X-Ray Diffraction (DXRD) has been used to correlate changes in bulk catalyst composition with Fischer-Tropsch activity over unsupported iron catalysts. It was found that the specific iron carbide phase formed was a function of particle size and temperature, with [var epsilon][prime]-Fe[sub 2.2]C formed over [sub X]-Fe[sub 2.5]C for smaller particle sizes and lower temperatures. While catalytic activity initially increased with the increase in carbide formation, deactivation was observed to be coincident with the [var epsilon][prime] [yields] [sub X] iron carbide transformation. This and subsequent hydrogen etching experiments indicate that the carbon formed from this transformation may act as nucleation sites for subsequent carbon deposition via the Boudouard reaction. All of the data obtained in this study are consistent with the competition model of Fischer-Tropsch synthesis, but while the carbide model does not appear to be a viable mechanism, the carbide itself may act as the catalyst.

• OSTI ID: 7027332
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 134:2; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010408* -- Coal
Lignite
& Peat-- C1 Processes-- (1987-)
36 MATERIALS SCIENCE
360602 -- Other Materials-- Structure & Phase Studies
CARBIDES
CARBON
CARBON COMPOUNDS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COHERENT SCATTERING
DEACTIVATION
DEPOSITION
DIFFRACTION
ELEMENTS
FISCHER-TROPSCH SYNTHESIS
IRON
IRON CARBIDES
IRON COMPOUNDS
KINETICS
METALS
NONMETALS
PARTICLE SIZE
PHASE STUDIES
PHASE TRANSFORMATIONS
REACTION KINETICS
SCATTERING
SIZE
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
X-RAY DIFFRACTION