A geometrical model of the active phase of hydrotreating catalysts

Kasztelan, S.; Toulhoat, H.; Grimblot, J.; Bonnelle, J.P.

doi:10.1016/s0166-9834(00)83333-3

Cited by 414 publications

(130 citation statements)

References 38 publications

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“…is the same as the global Co/Mo ratio of the catalyst, equal to 0.5. Taking into account the geometrical model proposed by Kasztelan based on a total substitution of Mo located at the edges and corners of the slabs by Co atoms [17], this ratio should correspond to MoS 2 slabs of 32 Ǻ long, a value in good agreement with the TEM measurements. On the contrary, for the CoMoP(0.7)-S the XPS analysis showed that the Co/Mo ratio of the slabs decreases to 0.4 (Fig.…”

Section: Tem Resultssupporting

confidence: 75%

X-ray Photoelectron Spectroscopy Surface Quantification of Sulfided CoMoP Catalysts – Relation Between Activity and Promoted Sites – Part I: Influence of the Co/Mo Ratio

Gandubert

Legens

Denis

et al. 2007

Oil & Gas Science and Technology - Rev. IFP

103

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Résumé -Quantification de surface de catalyseurs sulfures de type CoMoP par spectroscopie de photoélectrons X -Relation entre activité et sites promus -Partie I : Influence du rapport Co/Mo -Ce travail est dédié à la caractérisation de catalyseurs d'hydrotraitement CoMoP/Al 2 O 3 . Afin d'identifier l'environnement du cobalt et du molybdène, la spectroscopie de photoélectrons X (XPS), la microscopie électronique à transmission (MET) et les mesures d'activité ont été utilisées. En effet une approche quantitative de la caractérisation par XPS a été développée dans le cas de catalyseurs d'hydrotraitement de type CoMoP afin d'étudier l'effet du rapport atomique Co/Mo. Nous avons quantifié les différentes espèces présentes à la surface des catalyseurs et montré que le catalyseur présentant à la fois une activité maximale en hydrogénation du toluène et une concentration maximale de phase active mixte de type CoMoS, correspond au catalyseur de rapport atomique Co/Mo nominal de 0.5. Cependant la totalité des ions cobalt n'est pas engagée dans la phase mixte CoMoS. Abstract -X-ray Photoelectron Spectroscopy Surface Quantification of Sulfided CoMoP CatalystsRelation Between Activity and Promoted Sites -Part I: Influence of the Co/Mo Ratio -This work is dedicated to the characterization of CoMoP/Al 2 O 3 hydrotreatment catalysts. In order to identify the neighboring of cobalt and molybdenum, X-ray photoelectron spectroscopy (XPS), transmission electron spectroscopy (TEM) and activity measurements were used. Indeed, a quantitative XPS characterization was developed to study the effect of the Co/Mo atomic ratio on

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Section: Tem Resultssupporting

confidence: 75%

X-ray Photoelectron Spectroscopy Surface Quantification of Sulfided CoMoP Catalysts – Relation Between Activity and Promoted Sites – Part I: Influence of the Co/Mo Ratio

Gandubert

Legens

Denis

et al. 2007

Oil & Gas Science and Technology - Rev. IFP

103

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“…A maximum in activity is observed when the molar ratio (promoter)/(promotermolybdenum) is equal to 0.3, which (according to the geometrical model proposed by Kasztelan et al [17]) corresponds to a complete occupation of the edges of the MoS 2 slabs by the promoter [18,19]. At higher promoter loadings, the activity of the catalyst decreases.…”

Section: Discussionmentioning

confidence: 88%

Thioreduction of cyclopentanone and hydrodesulfurization of dibenzothiophene over sulfided nickel or cobalt-promoted molybdenum on alumina catalysts

Mijoin

Thévenin

Aguirre

et al. 1999

Applied Catalysis A: General

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“…The active sites are located on the edge of MoS2 slabs on alumina, so the ratio of 'edge Mo atoms'/'total Mo atoms' is the determining factor for the catalytic performance 53) , with an expected maximum of 30-40 Mo atoms per MoS2 slab. Consequently, a uniform MoS2 monolayer on alumina might exhibit lower activity than MoS2 slabs optimally dispersed on the surface.…”

Section: Nmmentioning

confidence: 99%

Sulfidation State and Sulfur Behavior on Mo-based HDS Catalysts Supported on TiO<sub>2</sub> Using <sup>35</sup>S Tracer Methods

Ishihara

2008

J. Jpn. Petrol. Inst.

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A35 S radioisotope pulse tracer method using 35 S-labeled H2S was used to investigate the sulfidation state of Mo-based catalysts supported on TiO2. Despite the coverage of Mo species on the TiO2 support, sulfidation of the TiO2 support still occurred at 300℃. The sulfided catalysts could be reduced under H2 atmosphere. A 35 S radioisotope tracer method using 35 S-labeled dibenzothiophene ([ 35 S]DBT) was used to determine the sulfur mobility on the working sulfided Mo/TiO2 catalysts. The amount of labile sulfur (So), which represents the amount of active sites, and the release rate constant of H2S, which represents the mobility of the active site (kRE), were estimated. Compared with Mo/Al2O3 catalyst, Mo/TiO2 catalyst had slightly higher So and about 2 times higher kRE, which indicate that new mobile active sites were formed on sulfided Mo/TiO2 catalyst. Comparison of the kRE and So of titania-based and alumina-based catalysts suggested that the active phase consisted of a 'TiMoS' phase exhibiting a promoting effect similar to the well-known 'CoMoS' phase (promotion of the MoS2 active phase by Ti atoms). Hydrodesulfurization (HDS) of DBT was evaluated over Mo catalysts supported on titania synthesized by the pH swing method, which provides a TiO2 carrier with a high specific surface area (134 m

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A geometrical model of the active phase of hydrotreating catalysts

Cited by 414 publications

References 38 publications

X-ray Photoelectron Spectroscopy Surface Quantification of Sulfided CoMoP Catalysts – Relation Between Activity and Promoted Sites – Part I: Influence of the Co/Mo Ratio

X-ray Photoelectron Spectroscopy Surface Quantification of Sulfided CoMoP Catalysts – Relation Between Activity and Promoted Sites – Part I: Influence of the Co/Mo Ratio

Thioreduction of cyclopentanone and hydrodesulfurization of dibenzothiophene over sulfided nickel or cobalt-promoted molybdenum on alumina catalysts

Sulfidation State and Sulfur Behavior on Mo-based HDS Catalysts Supported on TiO<sub>2</sub> Using <sup>35</sup>S Tracer Methods

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