Impact of Cr, Mn and Zr addition on Fe Fischer–Tropsch synthesis catalysis: Investigation at the active site level using SSITKA

Lohitharn, Nattaporn; Goodwin, James G.

doi:10.1016/j.jcat.2008.04.015

Cited by 101 publications

(51 citation statements)

References 26 publications

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“…Further studies with the Cr-, Mn-, and Zr-modified Fe catalysts suggested that the presence of these promoters increased the dispersion of Fe species but did not significantly change the reducibility or the BET surface area. [72] The intrinsic activity estimated by the SSITKA technique was similar for the Fe catalysts with and without these promoters, implying that the enhanced conversions were due to an increased number of active surface intermediates leading to hydrocarbon products. [72] Recently, an X-ray absorption near-edge structure (XANES) study was performed for the Mn-promoted Fe catalysts after reaction (with passivation in a 2 % O 2 /He mixture) to clarify the function of Mn.…”

Section: Co ! Co þC ð6þmentioning

confidence: 84%

“…[72] The intrinsic activity estimated by the SSITKA technique was similar for the Fe catalysts with and without these promoters, implying that the enhanced conversions were due to an increased number of active surface intermediates leading to hydrocarbon products. [72] Recently, an X-ray absorption near-edge structure (XANES) study was performed for the Mn-promoted Fe catalysts after reaction (with passivation in a 2 % O 2 /He mixture) to clarify the function of Mn. [73] The result suggested that Mn might substitute for octahedral sites in Fe 3 O 4 , corresponding to the formation of (Fe 1Àx Mn x ) 3 O 4 .…”

Section: Co ! Co þC ð6þmentioning

confidence: 84%

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Development of Novel Catalysts for Fischer–Tropsch Synthesis: Tuning the Product Selectivity

2010

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Fischer-Tropsch synthesis is a heterogeneous catalytic process for the production of clean hydrocarbon fuels or chemicals from synthesis gas (CO+H-2), which can be derived from non-petroleum feedstocks such as natural gas, coal, or biomass. Fischer-Tropsch synthesis has received renewed interests in recent years because of the global demand for a decreased dependence on petroleum for production of fuels and chemicals. The product distributions with conventional Fischer-Tropsch catalysts usually follow the Anderson-Schulz-Flory distribution and are typically unselective with regards to the formation of hydrocarbons from methane to waxes. Selectivity control is one of the key challenges of research into Fischer-Tropsch synthesis. This Review article summarizes the effects of key factors on catalytic properties, particularly the product selectivity, and highlights recent developments of novel Fischer-Tropsch catalysts and new strategies with an aim at controlling the product selectivity.National Natural Science Foundation of China [20625310, 20923004]; National Basic Research Program of China [2005CB221408, 2010CB732303]; Research Fund for the Doctoral Program of Higher Education [20090121110007]; Key Scientific Project of Fujian Province [2009HZ0002-1

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Section: Co ! Co þC ð6þmentioning

confidence: 84%

Section: Co ! Co þC ð6þmentioning

confidence: 84%

Development of Novel Catalysts for Fischer–Tropsch Synthesis: Tuning the Product Selectivity

2010

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“…Steady-State Isotopic-Transient Kinetic Analysis has evolved as one of the most useful transient methods in heterogeneous catalysis [2,[40][41][42][43]. The typical SSITKA experiment is carried out by (i) producing a step change in the reactant concentration by replacing reactant R with its isotope labeled counterpart *R and (ii) subsequently following the concentration of labeled *P as a function of time.…”

Section: Steady-state Isotopic-transient Kinetic Analysis (Ssitka)mentioning

confidence: 99%

Mechanistic Investigation of Heterogeneous Catalysis by Transient Infrared Methods

Chuang

Guzmán

2009

Top Catal

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This paper provides an overview of the use of various transient infrared methods to determine the role of infrared observable species in the mechanisms of the NO-CO reaction, heterogeneous ethylene hydroformylation, and photocatalytic oxidation of ethanol. The transient infrared methods with a judicious choice of ways in changing the concentration of reactants and their isotope counterparts produce responses, allowing (i) identification of the spectators, (ii) determination of active adsorbed species, and (iii) verification of kinetic models and their parameters. The method has also been recently extended to monitor infrared absorbance of photogenerated electrons during photocatalysis, correlating variation in the concentration of photogenerated electrons and adsorbed species. The specific discussion focuses on limitations of the approaches and the type of mechanistic information that can be obtained.

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“…The line at g & 2.1 was only observed for the sample of forsterite-91 mixed with distilled water and artificial seawater at pH 8.0 and supernatants ( Fig. It should be noted that Mn is a catalyst in FTT reactions that are very common in hydrothermal vents (Charlou et al 2002;Lohitharn & Goodwin Jr. 2008). Talik et al (2006) reported that synthetic forsterite crystals did not give any EPR spectra because, for this mineral, Fe(II) is present and this line is observable by EPR only at very low temperatures (< 5 K).…”

Section: X-ray Diffractometrymentioning

confidence: 98%

Interaction of forsterite-91 with distilled water and artificial seawater: a prebiotic chemistry experiment

Souza¹,

Carneiro²,

Baú³

et al. 2013

International Journal of Astrobiology

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In the present work, the interactions between forsterite-91 with distilled water and forsterite-91 with artificial seawater were studied at two pHs (2.0 and 8.0) using different techniques. A large increase in pH was observed for samples incubated at an initially acidic pH (2.0) due to the dissolution of forsterite-91 in distilled water and artificial seawater. Thus, in acidic hydrothermal vents, an increase in the amount of hydrocarbons and magnetite should be expected due to the release of Fe(II). The pH PZC decreased and the pH IEP increased when forsterite-91 was treated with distilled water and artificial seawater. The ions from the artificial seawater had an effect on zeta potential. Scanning electron microscopy (SEM) images and X-ray diffractograms showed halite in the samples of forsterite-91 mixed with artificial seawater. The presence of halite or adsorption of ions on the surface of forsterite-91 could affect the synthesis of magnetite and hydrocarbons in hydrothermal vents, due to a decrease in the dissolution rates of forsterite-91. The dissolution of forsterite-91 yields low concentrations of Fe(III) and Mn(II) as detected by electron paramagnetic resonance (EPR) spectroscopy. Microanalysis of forsterite-91 showed a higher amount of Mn, with an oxidation that was likely not + II, as Mn in supernatant solutions was only detected by EPR spectroscopy after mixing with artificial seawater at pH 2.0. As Fe(III) and Mn(II) are catalyst constituents of magnetite and manganese oxide, respectively, their presence is important for synthesis in hydrothermal vents. Etch pits were observed only in the forsterite-91 sample mixed with distilled water at pH 8.0. Na, Cl, S, Ca and K were detected in the samples mixed with artificial seawater by SEM-EDS. Si, Mg, Fe and Al were detected in almost all supernatant samples due to forsterite-91 dissolution. Cr was not dissolved in the experiments, thus Cr in the mineral could serve as an effective catalyst for Fischer Tropsch Types (FTT) reactions in hydrothermal vent systems. X-ray diffractograms of the original forsterite-91 also showed peaks arising from zeolites and clinochlore. After the samples were treated with artificial seawater, X-ray diffractograms showed the dissolution of zeolite. Experiments should be performed in the natural environment to verify the potential for zeolites to act as a catalyst in hydrothermal vents.

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Impact of Cr, Mn and Zr addition on Fe Fischer–Tropsch synthesis catalysis: Investigation at the active site level using SSITKA

Cited by 101 publications

References 26 publications

Development of Novel Catalysts for Fischer–Tropsch Synthesis: Tuning the Product Selectivity

Development of Novel Catalysts for Fischer–Tropsch Synthesis: Tuning the Product Selectivity

Mechanistic Investigation of Heterogeneous Catalysis by Transient Infrared Methods

Interaction of forsterite-91 with distilled water and artificial seawater: a prebiotic chemistry experiment

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