Fischer-Tropsch synthesis. Influence of the crystal size of iron active species on the activity and selectivity

• Published in: Applied catalysis. A, General Vol. 379; no. 1; pp. 105 - 110
• Main Authors: Cano, L.A., Cagnoli, M.V., Fellenz, N.A., Bengoa, J.F., Gallegos, N.G., Alvarez, A.M., Marchetti, S.G.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.05.2010; Elsevier
• Subjects: Atomic absorption analysis; Catalysis; Catalysts; Chemistry; Colloidal state and disperse state; Conversion; Crystals; Diffraction; Exact sciences and technology; Fe/MCM-41; Fe/SBA-15; Fischer-Tropsch synthesis; General and physical chemistry; Iron; Iron catalysts; Mesoporous materials; Porous materials; Surface physical chemistry; Synthesis; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Fe/MCM-41; Fischer-Tropsch synthesis; Mesoporous materials; Fe/SBA-15; Iron catalysts; Methane; Growth; Iron; Moessbauer spectrometry; Selectivity; Porous material; Solid; Structure; Catalyst support; Crystals; Fischer Tropsch synthesis; Transition metal; Conversion; X ray diffraction; Mesoporosity; Heterogeneous catalysis; Impregnation; Adsorption; Distribution; Catalyst
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2010.03.007

In the present work the influence of the crystal size of the iron active phase in the Fischer-Tropsch synthesis (FTS) is evaluated. The catalyst with higher crystal size (Fe/SBA-15) presented higher conversion, higher chain growth and lower CH 4 production. These results confirm that the FTS is a “structure sensitive” reaction in a sizes range within, approximately, 3–10 nm. In order to analyze the influence of the crystal size of the active phase in the Fischer-Tropsch synthesis (FTS), two iron catalysts, supported on MCM-41 and SBA-15, were prepared by incipient wetness impregnation and tested in this reaction. The solids were characterized by atomic absorption spectroscopy, N 2 adsorption, X-ray diffraction at low angles and Mössbauer spectroscopy. The activated catalysts showed the same iron species. However, the average crystal size of the active phase is about three times higher in SBA-15 than in MCM-41. Besides, both systems displayed a narrow size distribution. The catalyst with higher crystal size (Fe/SBA-15) presented higher conversion, higher chain growth and lower CH 4 production. These results would indicate that the FTS is a “structure sensitive” reaction in a sizes range within, approximately, 3–10 nm.