Iron Particle Size Effects for Direct Production of Lower Olefins from Synthesis Gas

Galvis, Hirsa M. Torres; Bitter, Johannes H.; Davidian, Thomas; Ruitenbeek, Matthijs; Dugulan, A. Iulian; Jong, Krijn P. de

doi:10.1021/ja304958u

Cited by 412 publications

(370 citation statements)

References 32 publications

(72 reference statements)

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“…10 and Supplementary Table 2). Furthermore, the catalyst with a bigger Fe particle size, displays a higher chain growth probability and consequently lower selectivity to methane, in agreement with previous studies 11 .…”

Section: Synthesis and Characterizationsupporting

confidence: 92%

Metal organic framework-mediated synthesis of highly active and stable Fischer-Tropsch catalysts

et al. 2015

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Depletion of crude oil resources and environmental concerns have driven a worldwide research on alternative processes for the production of commodity chemicals. Fischer-Tropsch synthesis is a process for flexible production of key chemicals from synthesis gas originating from non-petroleum-based sources. Although the use of iron-based catalysts would be preferred over the widely used cobalt, manufacturing methods that prevent their fast deactivation because of sintering, carbon deposition and phase changes have proven challenging. Here we present a strategy to produce highly dispersed iron carbides embedded in a matrix of porous carbon. Very high iron loadings (440 wt %) are achieved while maintaining an optimal dispersion of the active iron carbide phase when a metal organic framework is used as catalyst precursor. The unique iron spatial confinement and the absence of large iron particles in the obtained solids minimize catalyst deactivation, resulting in high active and stable operation.

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Section: Synthesis and Characterizationsupporting

confidence: 92%

Metal organic framework-mediated synthesis of highly active and stable Fischer-Tropsch catalysts

et al. 2015

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“…18,19,23,24 The effect of metal particle size on the catalytic performance has been extensively studied by several authors for cobalt, [25][26][27] with earliest contributions from Bartholomew 28 and Yermakov, 29 and for iron. 24,30,31 However, in the case of ruthenium, the number of research studies is certainly more limited. During the 80s, a few studies pointed out the increase in TOF for CO hydrogenation with increasing the size of Ru supported on alumina (or decreasing the metal dispersion from 0.78 to 0.16).…”

Section: Introductionmentioning

confidence: 99%

Ruthenium particle size and cesium promotion effects in Fischer–Tropsch synthesis over high-surface-area graphite supported catalysts

Eslava

Gascón

Kapteijn

et al. 2017

Catal. Sci. Technol.

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. Ruthenium particle size and cesium promotion effects in Fischer-Tropsch synthesis over high-surface-area graphite supported catalysts. Catalysis Science & Technology, 7(5), 1235-1244. DOI: 10.1039/c6cy02535h Important noteTo cite this publication, please use the final published version (if applicable). Please check the document version above. CopyrightOther than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons. Takedown policyPlease contact us and provide details if you believe this document breaches copyrights. We will remove access to the work immediately and investigate your claim. The effect of ruthenium particle size on Fischer-Tropsch synthesis (FTS) has been studied at 513 K, H2/CO = 2 and 15 bar. Supported Ru catalysts with particle sizes ranging from 1.7 to 12 nm were prepared by using different Ru loadings and two different high surface area graphite (HSAG) supports to minimize the metal-support interaction. In addition, the effect of promotion with Cs is also evaluated. Microcalorimetric characterization during CO adsorption and XPS reveal a clear interaction between Ru and Cs. The FTS with Ru-based catalysts is, independent of the presence of promoter, highly structure-sensitive when the Ru particle size is under 7 nm. In this range the turnover frequency (TOF) for CO conversion increases with particle size, reaching a near constant value for Ru particles larger than 7 nm. Cs promoted catalysts display lower TOF values than the corresponding unpromoted samples. This somewhat reduced activity is attributed to the stronger CO adsorption on Cs promoted catalysts, as demonstrated by CO adsorption microcalorimetry. Product selectivity depends also on Ru particle size. Selectivity to C5+ hydrocarbons increases with increasing Ru particle size. For Cs-promoted catalysts, the olefin to paraffin ratio in the C2-C4 hydrocarbons range is independent of the Ru particle size, whereas it decreases for the unpromoted catalysts, showing the prevailing influence of the promoter.

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“…The group of De Jong developed an FT process using a modified Fe catalyst that produces selectively lower olefins. 14 They speculated that such a selectivity is possible by the unique bonding characteristics of an iron-carbide phase as compared to that of metals such as Co or Ru.…”

Section: Introductionmentioning

confidence: 99%

“…: List of all elementary reaction steps surfaces and their corresponding forward and backward activation energies used to model FT synthesis over Ru (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). The reported forward and reverse energies are in relation to the most stable states found for the reactants and products and include zeropoint-energy corrections.…”

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confidence: 99%

Kinetic aspects of chain growth in Fischer–Tropsch synthesis

et al. 2017

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Microkinetics simulations are used to investigate the elementary reaction steps that control chain growth in the Fischer-Tropsch reaction. Chain growth in the FT reaction on stepped Ru surfaces proceeds via coupling of CH and CR surface intermediates. Essential to the growth mechanism are C-H dehydrogenation and C hydrogenation steps, whose kinetic consequences have been examined by formulating two novel kinetic concepts, the degree of chain-growth probability control and the thermodynamic degree of chain-growth probability control. For Ru the CO conversion rate is controlled by the removal of O atoms from the catalytic surface. The temperature of maximum CO conversion rate is higher than the temperature to obtain maximum chain-growth probability. Both maxima are determined by Sabatier behavior, but the steps that control chain-growth probability are different from those that control the overall rate. Below the optimum for obtaining long hydrocarbon chains, the reaction is limited by the high total surface coverage: in the absence of sufficient vacancies the CHCHR → CCHR + H reaction is slowed down. Beyond the optimum in chain-growth probability, CHCR + H → CHCHR and OH + H → H 2 O limit the chain-growth process. The thermodynamic degree of chain-growth probability control emphasizes the critical role of the H and free-site coverage and shows that at high temperature chain depolymerization contributes to the decreased chain-growth probability. That is to say, during the FT reaction chain growth is much faster than chain depolymerization, which ensures high chain-growth probability. The chain-growth rate is also fast compared to chain-growth termination and compared to the steps that control the overall CO conversion rate, which are O removal steps for Ru.

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Iron Particle Size Effects for Direct Production of Lower Olefins from Synthesis Gas

Cited by 412 publications

References 32 publications

Metal organic framework-mediated synthesis of highly active and stable Fischer-Tropsch catalysts

Metal organic framework-mediated synthesis of highly active and stable Fischer-Tropsch catalysts

Ruthenium particle size and cesium promotion effects in Fischer–Tropsch synthesis over high-surface-area graphite supported catalysts

Kinetic aspects of chain growth in Fischer–Tropsch synthesis

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