Center for Molecular Modeling - R.A. van Santen

Reactivity of CO on carbon covered cobalt surfaces in Fischer-Tropsch Synthesis

michel — Tue, 05 Nov 2013 10:56:39 +0000

L. Joos, I. Filot, S. Cottenier, E. Hensen, M. Waroquier, V. Van Speybroeck, R.A. van Santen

Journal of Physical Chemistry C

118 (10), 5317–5327

2014

Abstract

Fischer–Tropsch synthesis is an attractive process to convert alternative carbon sources, such as biomass, natural gas, or coal, to fuels and chemicals. Deactivation of the catalyst is obviously undesirable, and for a commercial plant it is of high importance to keep the catalyst active as long as possible during operating conditions. In this study, the reactivity of CO on carbon-covered cobalt surfaces has been investigated by means of density functional theory (DFT). An attempt is made to provide insight into the role of carbon deposition on the deactivation of two cobalt surfaces: the closed-packed Co(0001) surface and the corrugated Co(112̅1) surface. We also analyzed the adsorption and diffusion of carbon atoms on both surfaces and compared the mobility. Finally, the results for Co(0001) and Co(112̅1) are compared, and the influence of the surface topology is assessed.

DOI

http://dx.doi.org/10.1021/jp4109706

Private attachment

14_JPhysChemC_118,5317_Joos.pdf

Molecular dynamics study of the silica–water–SDA interactions

wim — Mon, 03 Oct 2011 12:18:12 +0000

B.M. Szyja, A.P.J. Jansen, T. Verstraelen, R.A. van Santen

Physical Chemistry Chemical Physics (PCCP)

11 (35), 7605-7610

2009

Abstract

In this paper we have applied the molecular dynamics simulations in order to analyse the role of the structure directing tetrapropylammonium ions in the aggregation process that leads to silicalite formation. We address the specific question of how the interactions between silica precursor species and tetrapropylammonium ions/water evolve during the formation of the larger aggregates, that show initial micropore formation from more elementary building blocks. We have followed the dynamics and changes in the position of the tetrapropylammonium ions into the formation of TPA-Si22 complexes. Moreover, the analysis based on the geometries of the systems being studied as well as the radial distribution function allowed us to predict the location of the TPA cations in fully formed nanoslabs. An interesting result is reported that the template cannot be accommodated any more in the newly formed cavities, but is pushed out of the channel like cavities to positions where in a later stage channel cross sections can be formed.

DOI

http://dx.doi.org/10.1039/B822859K

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09 phys. chem. chem. phys 11(35)7605 szyja.pdf

Multi-level Modeling of Silica–Template Interactions During Initial Stages of Zeolite Synthesis

wim — Mon, 03 Oct 2011 12:14:17 +0000

T. Verstraelen, B.M. Szyja, D. Lesthaeghe, R. Declerck, V. Van Speybroeck, M. Waroquier, A.P.J. Jansen, A. Aerts, L.R.A Follens, J.A. Martens, C. Kirschhock, R.A. van Santen

Topics in Catalysis

52 (9), 1261-1271

2009

Abstract

Zeolite synthesis is driven by structure-directing agents, such as tetrapropyl ammonium ions (TPA(+)) for Silicalite-1 and ZSM-5. However, the guiding role of these organic templates in the complex assembly to highly ordered frameworks remains unclear, limiting the prospects for advanced material synthesis. In this work, both static ab initio and dynamic classical modeling techniques are employed to provide insight into the interactions between TPA(+) and Silicalite-1 precursors. We find that as soon as the typical straight 10-ring channel of Silicalite-1 or ZSM-5 is formed from smaller oligomers, the TPA(+) template is partially squeezed out of the resulting cavity. Partial retention of the template in the cavity is, however, indispensable to prevent collapse of the channel and subsequent hydrolysis.

DOI

http://dx.doi.org/10.1007/s11244-009-9275-4

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09 topics cat 52(9)1261 verstraelen.pdf

Effect of carbon fouling of cobalt surfaces on the reactivity of CO in Fischer-Tropsch synthesis

samuel — Thu, 06 Feb 2020 12:44:35 +0000

L. Joos, I. Filot, M. Waroquier, S. Cottenier, V. Van Speybroeck, R.A. van Santen

ISBN/ISSN:

Talk

Conference / event / venue

14th International Conference on Theoretical Aspects of Catalysis (ICTAC-14 - 2012)

Vlissingen, The Netherlands

Tuesday, 26 June, 2012 to Saturday, 30 June, 2012

Reactivity of CO on clean and carbon covered cobalt surfaces in Fischer-Tropsch synthesis

lennart — Wed, 18 Jan 2012 22:13:58 +0000

L. Joos, I. Filot, M. Waroquier, S. Cottenier, V. Van Speybroeck, R.A. van Santen

p. 230

Poster

Conference / event / venue

XIIIth Netherlands' Catalysis and Chemistry Conference (NCCC XIII)

Noordwijkerhout, The Netherlands

Monday, 5 March, 2012 to Wednesday, 7 March, 2012

Abstract (private)

l_joos_ugent.pdf

Conference reference

NCCC-XIII

Reactivity of CO on clean and carbon covered cobalt surfaces in Fischer-Tropsch synthesis

lennart — Wed, 18 Jan 2012 22:12:32 +0000

L. Joos, I. Filot, M. Waroquier, S. Cottenier, V. Van Speybroeck, R.A. van Santen

http://www.cecam.org/workshop-3-699.html?poster_id=7746

Poster

Conference / event / venue

MolSim2012

Amsterdam

Monday, 9 January, 2012 to Friday, 20 January, 2012

Abstract (private)

l_joos_ugent.pdf

Conference reference

Molsim-2012