Description of coordinatively unsaturated sites regeneration over MoS2-based HDS catalysts using 35S experiments combined with computer simulations

Dumeignil, Franck; Paul, Jean‐François; Veilly, Edouard; Qian, Eika W.; Ishihara, Atsushi; Payen, Edmond; Kabe, Toshiaki

doi:10.1016/j.apcata.2005.04.025

Cited by 32 publications

(20 citation statements)

References 95 publications

(83 reference statements)

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“…Several studies have been focused on a deeper description of the catalytic active phases, promoter location, stabilization of sulfur vacancies, or the atomic description of model surface‐molecule interactions . Other studies have reported the adsorption energies of the S‐containing molecules on a catalyst surface and the charge transfer between the organic molecules and the metal active sites .…”

Section: Introductionmentioning

confidence: 99%

Refractory Character of 4,6‐Dialkyldibenzothiophenes: Structural and Electronic Instabilities Reign Deep Hydrodesulfurization

Valencia

García–Cruz

et al. 2018

ChemistrySelect

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We studied the most commonly S‐containing compounds present in crude oils, the so‐called 4,6‐dialkyldibenzothiophenes. The alkyl derivatives in this study were methyl, ethyl and isopropyl. Computationally rotating the alkyl substituents, we found differences in their stability. The most stable compound (isopropyl) was transformed into the most instable by changes in its structure. Aromaticity revealed the changes taking place upon structural modifications. The most refractory compound (isopropyl derivative) reduced much more its aromatic character than the methyl derivative. The interaction of these molecules with MoS2 confirmed their instable character upon adsorption. The stability of the refractory molecules and their destabilization prior to be transformed shed light into the key step that reign deep HDS.

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Section: Introductionmentioning

confidence: 99%

Refractory Character of 4,6‐Dialkyldibenzothiophenes: Structural and Electronic Instabilities Reign Deep Hydrodesulfurization

Valencia

García–Cruz

et al. 2018

ChemistrySelect

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“…12 Low valence sulfur species located on the MoS 2 edges were supposed earlier to be involved in H 2 activation, further research suggested that the presence of some hydrogencontaining species on the surface of unsupported overstoichiometric MoS 2+x , able to hydrogenate olefins in the absence of H 2 . 15 In the Co-Mo-S case, the most stable structure has sulfur vacancies and SH groups on the S dimmers, while a fully hydrogenated structure is found to be almost as stable. Dumeignil and colleagues showed that the CUS formation over MoS 2 is most likely to occur on the metallic edge through the release of an H 2 S molecule.…”

Section: Introductionmentioning

confidence: 88%

Insight into the effect of non-stoichiometric sulfur on a NiMoS hydrodesulfurization catalyst

Lai

Ren

et al. 2016

Catal. Sci. Technol.

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The finding provides new insight into NiMoS model that there is a sulfur dynamic equilibrium between NiMoS edge and gas phase. Since the evolution of non-stoechiometric sulfur proceed rapidly at initial stage of hydrodesulfurization reaction, the sulfur dynamic equilibrium does not draw so much attention. The results indicate that excess sulfur on Ni-Mo-S edge can be reduced by hydrogen to form SH groups and release H2S, which lead to a low sulfur covered NiMoS edge and a significant increase of coordinatively unsaturated sites (CUS), resulting in an outstanding HDS activity. Except for elucidating the effect of non-stoechiometric sulfur on NiMoS structure, a relationship among H2S partial pressure -Sx -HDS activity has been quantitatively studied. It is expected that these results will be used to deepen the understanding of HDS reaction over promoted MoS2 catalysts, as well as to guide the research of ultra-deep HDS of fuel oils.

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“…All of the previously mentioned research concludes that molecular hydrogen adsorption on the Mo-edge of the MoS 2 surface is heterolytic, and some groups even suggest that this is the rate-determining step of the overall reaction. It should be noted that Dumeignil et al 12 The investigation reported here is directed at determining the optimum adsorbed sulfur surface coverage (% S ) at typical SOFC operating conditions, that is, the higher temperature of 800°C and the lower H 2 S/H 2 anode fuel pressure ratio of 10 -5 . A further objective in our research is to study methods to remove excess adsorbed sulfur from the MoS 2 surface via the formation of S 2 (g) and SO 2 (g), to avoid SOFC anode degradation.…”

Section: Introductionmentioning

confidence: 98%

Modeling Hydrogen Sulfide Adsorption on Mo-Edge MoS₂ Surfaces under Solid Oxide Fuel Cell Conditions

2008

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We examine the degree to which sulfur-based fuel contaminants, such as hydrogen sulfide (H 2 S), can adsorb on the molybdenum sulfide-based anode of a solid oxide fuel cell (SOFC) under normal SOFC conditions. Our examination takes into account multiple adsorption/desorption events involving H 2 S and the fuel (H 2 ). By means of a kinetic model that allows us to approximate the rate of adsorbed oxygen formation based on experimental O 2-anion consumption at the triple-phase-boundary (TPB), we also consider the reaction mechanisms associated with the formation and desorption of H 2 O(g), SO 2 (g), and S 2 (g). Preferred adsorption sites, energies, transition states, and kinetic barriers are calculated for the resulting species, *SH x , *OH x , *SO x , and *S 2 (x ) 0-2). We have concluded that at typical SOFC operating conditions, the level of adsorbed sulfur on the MoS 2 anode surface will not exceed 25% (one S surface atom for every one Mo surface atom).

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Description of coordinatively unsaturated sites regeneration over MoS2-based HDS catalysts using 35S experiments combined with computer simulations

Abstract: catalysts (ca. 10 kcal.mol -1 ), which suggests that the mechanism on the promoted catalyst differs from that on the un-promoted one.

Cited by 32 publications

References 95 publications

Refractory Character of 4,6‐Dialkyldibenzothiophenes: Structural and Electronic Instabilities Reign Deep Hydrodesulfurization

Refractory Character of 4,6‐Dialkyldibenzothiophenes: Structural and Electronic Instabilities Reign Deep Hydrodesulfurization

Insight into the effect of non-stoichiometric sulfur on a NiMoS hydrodesulfurization catalyst

Modeling Hydrogen Sulfide Adsorption on Mo-Edge MoS₂ Surfaces under Solid Oxide Fuel Cell Conditions

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Description of coordinatively unsaturated sites regeneration over MoS2-based HDS catalysts using 35S experiments combined with computer simulations

Abstract: catalysts (ca. 10 kcal.mol -1 ), which suggests that the mechanism on the promoted catalyst differs from that on the un-promoted one.

Cited by 32 publications

References 95 publications

Refractory Character of 4,6‐Dialkyldibenzothiophenes: Structural and Electronic Instabilities Reign Deep Hydrodesulfurization

Refractory Character of 4,6‐Dialkyldibenzothiophenes: Structural and Electronic Instabilities Reign Deep Hydrodesulfurization

Insight into the effect of non-stoichiometric sulfur on a NiMoS hydrodesulfurization catalyst

Modeling Hydrogen Sulfide Adsorption on Mo-Edge MoS2 Surfaces under Solid Oxide Fuel Cell Conditions

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Modeling Hydrogen Sulfide Adsorption on Mo-Edge MoS₂ Surfaces under Solid Oxide Fuel Cell Conditions