Fischer–Tropsch synthesis: Activity of metallic phases of cobalt supported on silica

Gnanamani, Muthu Kumaran; Jacobs, Gary; Shafer, Wilson D.; Davis, Burtron H.

doi:10.1016/j.cattod.2013.03.004

Cited by 151 publications

(117 citation statements)

References 18 publications

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“…Gnanamani et al [83] produced hcp (hexagonal closepacked) and fcc (face-centred cubic) cobalt metal particles over silica support by employing different pre-treatments and observed higher carbon cobalt dispersion (5.06% in the case of hcp and 3.84% in the case of fcc) for the catalyst containing the hcp metallic phase; and subsequently higher carbon monoxide conversion (about 28 mol%) was achieved in this study, compared to that of fcc. Since the cobalt catalyst used in Fischer-Tropsch synthesis is expensive, hence, Loosdrecht et al [84] investigated the oxidation of nano-sized metallic cobalt during realistic F-T synthesis to cobalt oxide and concluded that this type of oxidation is independent of the support materials and could prevent the correct combination of reactor partial pressure of H 2 O and H 2 (P H2O /P H2 ).…”

Section: Overview Of Previous Work Regarding the Fischer-tropsch Synsupporting

confidence: 51%

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

Mahmoudi

Doustdar

et al. 2017

Biofuels Engineering

153

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For more than half a century, Fischer-Tropsch synthesis (FTS) of liquid hydrocarbons was a technology of great potential for the indirect liquefaction of solid or gaseous carbon-based energy sources (Coal-To-Liquid (CTL) and Gas-To-Liquid (GTL)) into liquid transportable fuels. In contrast with the past, nowadays transport fuels are mainly produced from crude oil and there is not considerable diversity in their variety. Due to some limitations in the first generation bio-fuels, the Second-Generation Biofuels (SGB)' technology was developed to perform the Biomass-To-Liquid (BTL) process. The BTL is a well-known multi-step process to convert the carbonaceous feedstock (biomass) into liquid fuels via FTS technology. This paper presents a brief history of FTS technology used to convert coal into liquid hydrocarbons; the significance of bioenergy and SGB are discussed as well. The paper covers the characteristics of biomass, which is used as feedstock in the BTL process. Different mechanisms in the FTS process to describe carbon monoxide hydrogenation as well as surface polymerization reaction are discussed widely in this paper. The discussed mechanisms consist of carbide, COinsertion and the hydroxycarbene mechanism. The surface chemistry of silica support is discussed. Silanol functional groups in silicon chemistry are explained extensively. The catalyst formulation in the Fischer Tropsch (F-T) process as well as F-T reaction engineering is discussed. In addition, the most common catalysts are introduced and the current reactor technologies in the F-T indirect liquefaction process are considered. process overview IntroductionThe over-reliance of the world's nations on conventional fossil fuels puts our planet in peril. The continuity of the current situation will result in the rise of a combined average temperature over global land and ocean surfaces by 5 ∘ C in 2100, bringing a rise in sea levels, food and water shortages and an increase in extreme weather events. The global warming, caused by humans, is one of the biggest threats to our future well-being [1]. In addition, oil reserves are limited and these reserves are decreasing dramatically. This reduction alongside the other relevant economic factors affects the world's oil prices. The need to run engines with the new generation of liquid fuels is inevitable. The investigations by the US Energy Information Administration (EIA) published in 2013 expressed a 56 percent increase in the world's energy consumption by the year 2040. Total world energy demand will have risen to 865 EJ (exajoule) by this year. The total world energy consumption was reported as 553 EJ in 2010. The outlook indicates that renewable energy is one of the fastest-growing energy sources in the world; where its usage increases 2.5 percent per year. Despite increasing success in the renewable energies, it is predicted that the fossil fuels will supply al-

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Section: Overview Of Previous Work Regarding the Fischer-tropsch Synsupporting

confidence: 51%

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

Mahmoudi

Doustdar

et al. 2017

Biofuels Engineering

153

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“…This may provide new insight for designing better catalyst; it is, however, important to note that the metalreactant/intermediate interaction and metal-support interaction may lead to rearrangement of the surface, which means that the dominating surfaces for hcp Co and fcc Co may change and correspondingly effect the mechanism. Moreover, whether the hcp or fcc phase is dominating in FTS depends on the activation conditions [134,135] and the rearrangement of the surface during real FT reaction condition has been demonstrated by both experimental and theoretical methods [136,137]. It is therefore hard to verify which phase (i.e.…”

Section: Co Activationmentioning

confidence: 99%

“…Despite the different proposals regarding the CO activation mechanism, it is agreed that hydrogenassisted CO activation is more kinetically favorable on ideal Co (0001). It is reported that hcp Co catalysts show higher FTS activity than fcc Co [134,135,[138][139][140][141]. Moreover, the larger sized Co catalysts, exposing mainly Co (0001) facets, exhibit higher FTS intrinsic reactivity compared to the smaller sized Co catalysts below 6 nm, possibly because the latter has strongly bonded carbon and oxygen surface species acting as site blocking species, and small particles may also be easily oxidized by the water vapor [6,92,142], suggesting a large contribution of Co (0001) to the reaction under reaction condition.…”

Section: Co Activationmentioning

confidence: 99%

Recent Progresses in Understanding of Co-Based Fischer–Tropsch Catalysis by Means of Transient Kinetic Studies and Theoretical Analysis

Yang

Chen

et al. 2014

Catal Lett

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During the last years it has been an increasing focus on fundamental studies of the Fischer-Tropsch synthesis (FTS). Steady-state isotopic transient kinetic analysis and first principles investigation have proven to be important methods in studying the reaction mechanism of FTS. The present contribution deals with recent progresses in understanding of the F-T mechanism on Co catalysts based on combined DFT calculations, in situ characterization, steady-state isotopic transient kinetic analysis and microkinetics. A brief outlook into future perspectives of the FTS for converting synthesis gas from different carbon sources to fuels and chemicals is also provided.

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“…Surface defect sites such as kinks and steps have beeen shown via DFT calculations to allow carbon monoxide (CO) and other gas molecules to bind to the site more easily [41]. The high binding energy possibly encourages CO dissociation and consequently increases the FTS turnover rate [42].…”

mentioning

confidence: 99%

X-ray spectroscopic and scattering methods applied to the characterisation of cobalt-based Fischer–Tropsch synthesis catalysts

Herbert

Sénécal

Martin

et al. 2016

Catal. Sci. Technol.

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(2016) 'X-ray spectroscopic and scattering methods applied to the characterisation of cobalt-based FischerTropsch synthesis catalysts.', Catalysis science and technology., 6 (15). pp. 5773-5791. Further information on publisher's website:http://dx.doi.org/10.1039/C6CY00581KPublisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract: This review aims to critically assess the use of X-ray techniques, both of a scattering (e.g. X-ray diffraction (XRD), Pair Distribution Function (PDF)) and spectroscopic nature (X-ray Absorption spectroscopy (XAFS)), in the study of cobalt-based Fisher-Tropsch Synthesis (FTS) catalysts. In particular, the review will focus on how these techniques have been successfully used to describe the salient characteristics of these catalysts that govern subsequent activity and selectivity, as well as to afford insight into deactivation phenomena that have seemingly stifled their application. We discuss how these X-ray-based techniques have been used to yield insight into the bulk structure, the catalyst surface, oxidation states, local (cobalt) geometry, and elemental composition of particles, primarily from a 1D perspective but we also highlight how, with recent developments in advanced X-ray characterisation methods, crucial information can now be obtained in 2D and 3D. The examples chosen focus on data acquired in situ/operando, under realistic operating conditions and during activation which often allow for obtaining a more relevant perspective on the changes in catalyst structure that accompany a change in catalyst performance. We conclude with a perspective on some of the challenges that beset the Co-based FTS technology and discuss how X-ray based techniques could be used to solve them.2

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Fischer–Tropsch synthesis: Activity of metallic phases of cobalt supported on silica

Cited by 151 publications

References 18 publications

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

A review of Fischer Tropsch synthesis process, mechanism, surface chemistry and catalyst formulation

Recent Progresses in Understanding of Co-Based Fischer–Tropsch Catalysis by Means of Transient Kinetic Studies and Theoretical Analysis

X-ray spectroscopic and scattering methods applied to the characterisation of cobalt-based Fischer–Tropsch synthesis catalysts

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