Fischer Tropsch synthesis : influence of Mn on the carburization rates and activities of Fe-based catalysts by TPR-EXAFS/XANES and catalyst testing.

Journal Article · Thu Mar 24 00:00:00 EDT 2011 · Appl. Catal. A

DOI:https://doi.org/10.1021/jp111728h· OSTI ID:1021311

Ribeiro, M C; Jacobs, G; Pendyala, R; Davis, B H; Cronauer, D C; Kropf, A J; Marshall, C L ^[1]

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1. Chemical Sciences and Engineering Division

Fe-based catalysts containing different amounts of Mn were tested for Fischer-Tropsch synthesis using a stirred tank reactor at 270 C, 1.21 MPa, and H{sub 2}:CO = 0.7. Catalyst activation by carburization with 10% CO/He was followed by Temperature Programmed Reduction/X-ray Absorption Spectroscopy (TPR-EXAFS/XANES) from room temperature to 300 C. {gamma}-Fe{sub 2}O{sub 3} was converted into iron carbides, whereas MnO{sub x} was reduced to oxygen deficient MnO. Mn hindered Fe carburization, such that the carburized catalyst displayed higher Fe{sub 3}O{sub 4} content than the catalyst without Mn. EXAFS fitting indicates that the carburized catalyst contained a mixture of Hgg carbide, Fe{sub 3}O{sub 4}, and Mn oxides. Increasing Mn content led to higher CH{sub 4} and light product selectivities, and lower light olefin selectivities. Higher and stable conversions were obtained with a catalyst containing an almost equimolar Fe/Mn ratio relative to the catalyst without Mn. Selectivity trends are attributed to the higher WGS rates observed on the FeMn catalysts, consistent with the structural differences observed.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: FE; USDOE Office of Science (SC); NETL; Kentucky Governor's Office of Energy Policy
• DOE Contract Number: DE-AC02-06CH11357
• OSTI ID: 1021311
• Report Number(s): ANL/CSE/JA-68183; TRN: US201116%%707
• Journal Information: Appl. Catal. A, Vol. 115, Issue 11 ; Mar. 24, 2011
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
CARBURIZATION
CATALYSTS
FISCHER-TROPSCH SYNTHESIS
IRON
IRON CARBIDES
MANGANESE
TESTING
AMBIENT TEMPERATURE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K