The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
E Van Steen - One of the best experts on this subject based on the ideXlab platform.
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silica supported cobalt fischer tropsch catalysts effect of Pore Diameter of support
Catalysis Today, 2002Co-Authors: A M Saib, Michael Claeys, E Van SteenAbstract:Abstract The influence of the effect of average Pore Diameter of silica support on the physical and chemical properties of supported cobalt catalysts and their performance in the Fischer–Tropsch synthesis was investigated. Silicas with different mean Pore Diameter (20, 40, 60, 100 and 150 A) were impregnated with cobalt nitrate to produce catalysts containing 20 wt.% cobalt. The metal crystallite size and degree of reduction was found to increase with increasing Pore Diameter of the support for supports with an average Pore Diameter larger or equal to 40 A, and hence the dispersion decreased. In impregnated catalysts, the metal crystallites seems to appear in clusters on the support. With increasing average Pore Diameter, the size of these clusters increases. In the Fischer–Tropsch synthesis, the 100 A supported catalyst proved to be the most active and selective catalyst for hydrocarbon formation. The C5+ and methane selectivity passed through a maximum and minimum at the 100 A supported catalyst, respectively, which can be explained quantitatively using the reactant transport model proposed by Iglesia et al.
B R Walsh - One of the best experts on this subject based on the ideXlab platform.
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effects of Pore Diameter on particle size phase and turnover frequency in mesoporous silica supported cobalt fischer tropsch catalysts
Applied Catalysis A-general, 2010Co-Authors: I T Ghampson, C Newman, L Kong, E Pier, K D Hurley, Rachel A Pollock, B R WalshAbstract:Abstract A series of mesoporous silica supported cobalt catalysts for the Fischer–Tropsch reaction with Pore Diameters from 3 to 22 nm was synthesized and characterized. Detailed X-ray diffraction measurements were used to determine the composition and particle Diameters of the metal fraction, analyzed as a three-phase system containing Co fcc , Co hcp and CoO. Catalyst properties were determined at three stages of catalyst history: (1) after the initial calcination step to thermally decompose the catalyst precursor into Co 3 O 4 , (2) after the hydrogen reduction step to activate the catalyst to Co and (3) after the FT reaction. Small Co hcp particles were detected in all reduced catalysts contributing significantly to the Co surface area. The reaction rate increased with the Pore Diameter of the silica support. The results indicate the importance of careful catalyst characterization in determining the factors that contribute to reactivity. In addition, the identification of significant quantities of two cobalt metal phases suggests that further study of the intrinsic activity of each phase, as well as the structural features of the supports that determine the distribution of cobalt phases and particle sizes is warranted.
L Kong - One of the best experts on this subject based on the ideXlab platform.
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effects of Pore Diameter on particle size phase and turnover frequency in mesoporous silica supported cobalt fischer tropsch catalysts
Applied Catalysis A-general, 2010Co-Authors: I T Ghampson, C Newman, L Kong, E Pier, K D Hurley, Rachel A Pollock, B R WalshAbstract:Abstract A series of mesoporous silica supported cobalt catalysts for the Fischer–Tropsch reaction with Pore Diameters from 3 to 22 nm was synthesized and characterized. Detailed X-ray diffraction measurements were used to determine the composition and particle Diameters of the metal fraction, analyzed as a three-phase system containing Co fcc , Co hcp and CoO. Catalyst properties were determined at three stages of catalyst history: (1) after the initial calcination step to thermally decompose the catalyst precursor into Co 3 O 4 , (2) after the hydrogen reduction step to activate the catalyst to Co and (3) after the FT reaction. Small Co hcp particles were detected in all reduced catalysts contributing significantly to the Co surface area. The reaction rate increased with the Pore Diameter of the silica support. The results indicate the importance of careful catalyst characterization in determining the factors that contribute to reactivity. In addition, the identification of significant quantities of two cobalt metal phases suggests that further study of the intrinsic activity of each phase, as well as the structural features of the supports that determine the distribution of cobalt phases and particle sizes is warranted.
C Newman - One of the best experts on this subject based on the ideXlab platform.
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effects of Pore Diameter on particle size phase and turnover frequency in mesoporous silica supported cobalt fischer tropsch catalysts
Applied Catalysis A-general, 2010Co-Authors: I T Ghampson, C Newman, L Kong, E Pier, K D Hurley, Rachel A Pollock, B R WalshAbstract:Abstract A series of mesoporous silica supported cobalt catalysts for the Fischer–Tropsch reaction with Pore Diameters from 3 to 22 nm was synthesized and characterized. Detailed X-ray diffraction measurements were used to determine the composition and particle Diameters of the metal fraction, analyzed as a three-phase system containing Co fcc , Co hcp and CoO. Catalyst properties were determined at three stages of catalyst history: (1) after the initial calcination step to thermally decompose the catalyst precursor into Co 3 O 4 , (2) after the hydrogen reduction step to activate the catalyst to Co and (3) after the FT reaction. Small Co hcp particles were detected in all reduced catalysts contributing significantly to the Co surface area. The reaction rate increased with the Pore Diameter of the silica support. The results indicate the importance of careful catalyst characterization in determining the factors that contribute to reactivity. In addition, the identification of significant quantities of two cobalt metal phases suggests that further study of the intrinsic activity of each phase, as well as the structural features of the supports that determine the distribution of cobalt phases and particle sizes is warranted.
E Pier - One of the best experts on this subject based on the ideXlab platform.
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effects of Pore Diameter on particle size phase and turnover frequency in mesoporous silica supported cobalt fischer tropsch catalysts
Applied Catalysis A-general, 2010Co-Authors: I T Ghampson, C Newman, L Kong, E Pier, K D Hurley, Rachel A Pollock, B R WalshAbstract:Abstract A series of mesoporous silica supported cobalt catalysts for the Fischer–Tropsch reaction with Pore Diameters from 3 to 22 nm was synthesized and characterized. Detailed X-ray diffraction measurements were used to determine the composition and particle Diameters of the metal fraction, analyzed as a three-phase system containing Co fcc , Co hcp and CoO. Catalyst properties were determined at three stages of catalyst history: (1) after the initial calcination step to thermally decompose the catalyst precursor into Co 3 O 4 , (2) after the hydrogen reduction step to activate the catalyst to Co and (3) after the FT reaction. Small Co hcp particles were detected in all reduced catalysts contributing significantly to the Co surface area. The reaction rate increased with the Pore Diameter of the silica support. The results indicate the importance of careful catalyst characterization in determining the factors that contribute to reactivity. In addition, the identification of significant quantities of two cobalt metal phases suggests that further study of the intrinsic activity of each phase, as well as the structural features of the supports that determine the distribution of cobalt phases and particle sizes is warranted.