Atomic-scale insight into adsorption of sterically hindered dibenzothiophenes on MoS and Co-Mo-S hydrotreating catalysts

A.K. Tuxen; H.G. Füchtbauer; Burcin Temel; Berit Hinnemann; H. Topsoe; K.G. Knudsen; F. Besenbacher; J.V. Lauritsen

doi:10.1016/j.jcat.2012.08.004

Atomic-scale insight into adsorption of sterically hindered dibenzothiophenes on MoS and Co-Mo-S hydrotreating catalysts

A.K. Tuxen, H.G. Füchtbauer, Burcin Temel, Berit Hinnemann, H. Topsoe, K.G. Knudsen, F. Besenbacher, J.V. Lauritsen

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

Abstract

Sterical hindrance of large S-containing molecules is known to be a significant cause of low hydrodesulfurization activity. To shed light on the atomistic aspects of such steric effects, we use atom-resolved scanning tunneling microscopy (STM) to probe the detailed adsorption configurations of dibenzothiophene (DBT) and alkyl-substituted DBT molecules on both unpromoted and Co-promoted MoS nanoclusters. We show that the unsubstituted DBT molecule can adsorb directly through its sulfur atom at sulfur vacancies on the nanocluster. However, only vacancies at corner sites are found to be accessible for DBT adsorption. In a similar way, DBT is found to adsorb on the Co-Mo-S sites exposed at the corners of the Co-promoted nanoclusters. In contrast, the 4,6-DMDBT molecule adsorbs in a flat configuration on the brim sites of the MoS clusters without the requirement of a nearby vacancy. Our findings support a model where hydrogenation and sulfur extrusion may take place on different sites.

Original language	English
Journal	Journal of Catalysis
Volume	295
Pages (from-to)	146-154
Number of pages	9
ISSN	0021-9517
DOIs	https://doi.org/10.1016/j.jcat.2012.08.004
Publication status	Published - 1 Nov 2012

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10.1016/j.jcat.2012.08.004

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title = "Atomic-scale insight into adsorption of sterically hindered dibenzothiophenes on MoS and Co-Mo-S hydrotreating catalysts",

abstract = "Sterical hindrance of large S-containing molecules is known to be a significant cause of low hydrodesulfurization activity. To shed light on the atomistic aspects of such steric effects, we use atom-resolved scanning tunneling microscopy (STM) to probe the detailed adsorption configurations of dibenzothiophene (DBT) and alkyl-substituted DBT molecules on both unpromoted and Co-promoted MoS nanoclusters. We show that the unsubstituted DBT molecule can adsorb directly through its sulfur atom at sulfur vacancies on the nanocluster. However, only vacancies at corner sites are found to be accessible for DBT adsorption. In a similar way, DBT is found to adsorb on the Co-Mo-S sites exposed at the corners of the Co-promoted nanoclusters. In contrast, the 4,6-DMDBT molecule adsorbs in a flat configuration on the brim sites of the MoS clusters without the requirement of a nearby vacancy. Our findings support a model where hydrogenation and sulfur extrusion may take place on different sites.",

author = "A.K. Tuxen and H.G. F{\"u}chtbauer and Burcin Temel and Berit Hinnemann and H. Topsoe and K.G. Knudsen and F. Besenbacher and J.V. Lauritsen",

year = "2012",

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doi = "10.1016/j.jcat.2012.08.004",

language = "English",

volume = "295",

pages = "146--154",

journal = "Journal of Catalysis",

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Atomic-scale insight into adsorption of sterically hindered dibenzothiophenes on MoS and Co-Mo-S hydrotreating catalysts. / Tuxen, A.K.; Füchtbauer, H.G.; Temel, Burcin et al.
In: Journal of Catalysis, Vol. 295, 01.11.2012, p. 146-154.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

TY - JOUR

T1 - Atomic-scale insight into adsorption of sterically hindered dibenzothiophenes on MoS and Co-Mo-S hydrotreating catalysts

AU - Tuxen, A.K.

AU - Füchtbauer, H.G.

AU - Temel, Burcin

AU - Hinnemann, Berit

AU - Topsoe, H.

AU - Knudsen, K.G.

AU - Besenbacher, F.

AU - Lauritsen, J.V.

PY - 2012/11/1

Y1 - 2012/11/1

N2 - Sterical hindrance of large S-containing molecules is known to be a significant cause of low hydrodesulfurization activity. To shed light on the atomistic aspects of such steric effects, we use atom-resolved scanning tunneling microscopy (STM) to probe the detailed adsorption configurations of dibenzothiophene (DBT) and alkyl-substituted DBT molecules on both unpromoted and Co-promoted MoS nanoclusters. We show that the unsubstituted DBT molecule can adsorb directly through its sulfur atom at sulfur vacancies on the nanocluster. However, only vacancies at corner sites are found to be accessible for DBT adsorption. In a similar way, DBT is found to adsorb on the Co-Mo-S sites exposed at the corners of the Co-promoted nanoclusters. In contrast, the 4,6-DMDBT molecule adsorbs in a flat configuration on the brim sites of the MoS clusters without the requirement of a nearby vacancy. Our findings support a model where hydrogenation and sulfur extrusion may take place on different sites.

AB - Sterical hindrance of large S-containing molecules is known to be a significant cause of low hydrodesulfurization activity. To shed light on the atomistic aspects of such steric effects, we use atom-resolved scanning tunneling microscopy (STM) to probe the detailed adsorption configurations of dibenzothiophene (DBT) and alkyl-substituted DBT molecules on both unpromoted and Co-promoted MoS nanoclusters. We show that the unsubstituted DBT molecule can adsorb directly through its sulfur atom at sulfur vacancies on the nanocluster. However, only vacancies at corner sites are found to be accessible for DBT adsorption. In a similar way, DBT is found to adsorb on the Co-Mo-S sites exposed at the corners of the Co-promoted nanoclusters. In contrast, the 4,6-DMDBT molecule adsorbs in a flat configuration on the brim sites of the MoS clusters without the requirement of a nearby vacancy. Our findings support a model where hydrogenation and sulfur extrusion may take place on different sites.

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DO - 10.1016/j.jcat.2012.08.004

M3 - Journal article

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SN - 0021-9517

VL - 295

SP - 146

EP - 154

JO - Journal of Catalysis

JF - Journal of Catalysis

ER -

Atomic-scale insight into adsorption of sterically hindered dibenzothiophenes on MoS and Co-Mo-S hydrotreating catalysts

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