Improved flow technique for measurement of hydrogen chemisorption on metal catalysts

Jones, R. D.; Bartholomew, Calvin H.

doi:10.1016/s0166-9834(00)80940-9

Cited by 119 publications

(42 citation statements)

References 23 publications

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“…The cobalt dispersion (D, %) was calculated assuming that two cobalt sites were covered by one hydrogen molecule [16], and that rhenium did not adsorb any hydrogen [17]. The cobalt particle size (d, nm) was calculated from the cobalt dispersion by the following formula [18]:…”

Section: Methodsmentioning

confidence: 99%

Studies of Macroporous Structured Alumina Based Cobalt Catalysts for Fischer–Tropsch Synthesis

et al. 2011

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Macroporous structured (MPS)-Al 2 O 3 support was synthesised from Al 2 O 3 nanoparticles with polystyrene beads as a sacrificing agent. A MPS-Al 2 O 3 with uniformly spherical and interconnected pores throughout the sample was obtained. The MPS-Al 2 O 3 was characterized and used as support for cobalt Fischer-Tropsch catalysts. Surface kinetic parameters and intrinsic activity of the catalysts were determined by steady-state isotopic transient kinetic analysis (SSITKA) at 483 K, 1.85 bar and H 2 /CO = 10. The catalyst was compared with conventional a-and c-Al 2 O 3 supported cobalt catalysts. The results show that the MPS-Al 2 O 3 support seems to combine the advantages of a-Al 2 O 3 and c-Al 2 O 3 as support materials, with activity and selectivity comparable to conventional Co/c-Al 2 O 3 and Co/a-Al 2 O 3 , respectively.

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Section: Methodsmentioning

confidence: 99%

Studies of Macroporous Structured Alumina Based Cobalt Catalysts for Fischer–Tropsch Synthesis

et al. 2011

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“…Furthermore, in order to calculate the dispersion, it was assumed that two cobalt surface atoms were covered by one hydrogen molecule [20], and that rhenium did not contribute to the amount of hydrogen adsorbed. The apparent cobalt metal particle size (d(Co 0 ) uncorrected ) can be calculated from the cobalt dispersion (D) by assuming spherical, uniform cobalt metal particles with site density of 14.6 at./nm 2 [21]. These assumptions give the following formula:…”

Section: Hydrogen Chemisorptionmentioning

confidence: 99%

Electron Microscopy Study of γ-Al2O3 Supported Cobalt Fischer–Tropsch Synthesis Catalysts

et al. 2008

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Three supported catalysts containing 20 wt% cobalt and 0.5 wt% rhenium were subjected to electron microscopy studies in their calcined state. The catalysts were prepared by incipient wetness impregnation of c-Al 2 O 3 supports of different pore characteristics with aqueous solutions of cobalt nitrate hexahydrate and perrhenic acid. The influence of the support on the Co 3 O 4 crystallite size and distribution was studied by X-ray diffraction and electron microscopy. There was a positive correlation between the pore diameter of the support and the post calcination Co 3 O 4 crystallite size. On all three c-Al 2 O 3 supports, Co 3 O 4 was present as aggregates of many crystallites (20-270 nm in size). Cobalt oxide did not crystallise as independent crystallites, but as an interconnected network, with a roughly common crystallographic orientation, within the matrix pore structure. The internal variations in crystallite size between the catalysts were maintained after reduction. Fischer-Tropsch synthesis was carried out in a fixed-bed reactor at industrial conditions (T = 483 K, P = 20 bar, H 2 /CO = 2.1). Although the cobalt-time yields varied significantly (4.6-6.7 9 10 -3 mol CO/mol Co s), the site-time yields were constant (63-68 9 10 -3 s -1 ) for the three samples. The C 5? selectivity could not be correlated to the cobalt oxide aggregate size and is more likely related to the cobalt particle size and chemical properties of the c-Al 2 O 3 support.

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“…[20,25]. The average particle size of Co 0 , assuming spherical shape, was estimated according to [26][27][28]:…”

Section: Catalyst Characterization Methodsmentioning

confidence: 99%

Investigation of Mixtures of a Co-Based Catalyst and a Cu-Based Catalyst for the Fischer–Tropsch Synthesis with Bio-Syngas: The Importance of Indigenous Water

et al. 2011

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A series of different mechanical mixtures of a narrow-pore Co/c-Al 2 O 3 catalyst and a Cu-based WGScatalyst has been investigated in the low-temperature Fischer-Tropsch synthesis (483 K, 20 bar) with a model bio-syngas (H 2 /CO = 1.0) in a fixed-bed reactor. The higher the fraction of WGS-catalyst in the mixture, the lower is the Co-catalyst-time yield to hydrocarbons. This is ascribed to a strong positive kinetic effect of water on the Fischer-Tropsch rate of the Co-catalyst, showing the importance of the indigenously produced water, especially in fixed-bed reactors where the partial pressure of water is zero at the reactor inlet. A preliminary kinetic modeling suggests that the reaction order in P H 2 O is 0.3 for the Co/ c-Al 2 O 3 catalyst in the range of the studied reactor-average partial pressures of water (i.e., 0.04-1.2 bar).

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Improved flow technique for measurement of hydrogen chemisorption on metal catalysts

Cited by 119 publications

References 23 publications

Studies of Macroporous Structured Alumina Based Cobalt Catalysts for Fischer–Tropsch Synthesis

Studies of Macroporous Structured Alumina Based Cobalt Catalysts for Fischer–Tropsch Synthesis

Electron Microscopy Study of γ-Al2O3 Supported Cobalt Fischer–Tropsch Synthesis Catalysts

Investigation of Mixtures of a Co-Based Catalyst and a Cu-Based Catalyst for the Fischer–Tropsch Synthesis with Bio-Syngas: The Importance of Indigenous Water

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