Adsorption and dissociation of H2 and H2S on MoS2 and NiMoS catalysts

Sun, Mingyong; Nelson, Alan E.; Adjaye, John

doi:10.1016/j.cattod.2005.04.002

Cited by 105 publications

(67 citation statements)

References 28 publications

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“…They found that the most likely products of CO hydrogenation are CH 4 and CO 2 , in agreement with the experiment results [8]. However, according to the studies of Travert et al [32], Cristol et al [29,34], Raybaud et al [33], and Sun et al [28,36], the two terminations considered by Huang and Cho [35] do not seem to reflect the realistic catalyst. They are not stable for H 2 S/H 2 pressure ratios in the range 0.0001 < p(H 2 S)/p(H 2 ) < 10000 [34].…”

Section: Introductionsupporting

confidence: 75%

“…They are not stable for H 2 S/H 2 pressure ratios in the range 0.0001 < p(H 2 S)/p(H 2 ) < 10000 [34]. For p(H 2 S)/p(H 2 ) < 0.05 corresponding to the realistic catalytic system the MoS 2 (10-10) surface is terminated by Mo metal sheets covered with about 50% sulfur and by S sheets with about 4 50% sulfur vacancies [28,29,[32][33][34]36] as mentioned above. These terminations have been considered in the present work.…”

Section: Introductionmentioning

confidence: 99%

“…Using a periodic single-sheet model, Sun et al [28] studied H 2 adsorption and dissociation on MoS 2 and NiMoS, and found that homolytic H 2 dissociation to form two S-H groups is thermodynamically preferred over heterolytic dissociation yielding one S-H and one Mo-H group, and the latter is kinetically favored. On the other hand, Bollinger et al [27] found the most stable hydrogen adsorption to be the formation of two S-H groups on the S edge.…”

Section: Introductionmentioning

confidence: 99%

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CO hydrogenation reaction on sulfided molybdenum catalysts

Shi

Jiao

Hermann

et al. 2009

Journal of Molecular Catalysis A: Chemical

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Adsorption of reaction intermediates appearing during CO hydrogenation at the sulfur covered MoS 2 (10-10) surfaces, Mo-termination with 42% S coverage and S-termination with 50% S coverage, are investigated systematically using periodic density functional theory methods. Computed vibrational frequencies of all intermediates are compared with observed data from infrared (IR) spectroscopy allowing a detailed interpretation and assignment of the different features in the experimental spectra. The pathway for CO hydrogenation on both terminations has been studied in detail where the most likely reaction path involves C 1 type surface species in the sequence in agreement with experiment.

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Section: Introductionsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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CO hydrogenation reaction on sulfided molybdenum catalysts

Shi

Jiao

Hermann

et al. 2009

Journal of Molecular Catalysis A: Chemical

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“…Planview TEM along (0001), indicates that a next WS2 layer grows either from the grain boundaries of the first layer or on the basal plane of the first layer. As proposed in our earlier work, -SH groups at the edges of WS2 crystals can be reactive sites for WF6 reaction 24,41,42 . In addition, adsorption of WF6 on the basal plane of WS2 crystals cannot be excluded, e.g., at reactive sites that are created on the basal plane by H2 plasma.…”

Section: Growth Mode In the Linear Growth Regimementioning

confidence: 91%

Nucleation mechanism during WS2 plasma enhanced atomic layer deposition on amorphous Al2O3 and sapphire substrates

Groven

Mehta

Bender

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The structure, crystallinity and properties of as-deposited two-dimensional (2D) transition metal dichalcogenides are determined by nucleation mechanisms in the deposition process. 2D materials grown by atomic layer deposition (ALD) in absence of a template, are polycrystalline or amorphous. Little is known about their nucleation mechanisms.Therefore, we investigate the nucleation behavior of WS2 during plasma enhanced ALD from WF6, H2 plasma and H2S at 300 °C on amorphous ALD Al2O3 starting surface and on monocrystalline, bulk sapphire. Preferential interaction of the precursors with the Al2O3 starting surface promotes fast closure of the WS2 layer. The WS2 layers are fully continuous at WS2 content corresponding to only 1.2 WS2 monolayers. On amorphous Al2O3, (0002) textured and polycrystalline WS2 layers form with grain size of 5 nm to 20 nm due to high nucleation density (~10 14 nuclei/cm 2 ). The WS2 growth mode changes from 2D (layer-by-layer) growth on the initial Al2O3 surface to threedimensional (Volmer-Weber) growth after WS2 layer closure. Further growth proceeds from both WS2 basal planes in register with the underlying WS2 grain, and from or over grain boundaries of the underlying WS2 layer with different in-plane orientation. In contrast, on monocrystalline sapphire, WS2 crystal grains can locally align along a preferred in-plane orientation. Epitaxial seeding occurs locally albeit a large portion of crystals remain randomly oriented, presumably due to the low deposition temperature.The WS2 sheet resistance is 168 MΩµm suggesting that charge transport in the WS2 layers is limited by grain boundaries.3

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“…But Ni atoms preferred the metal edges in "NiMoS" phase. Nickel facilitated the adsorption of H2S and H2 and the mobility of hydrogen, the adsorption on NiMoS were studied by density-functional theory (DFT) calculations [4]. The presence of Ni activates the Mo-S bond, produced a polarization at this bond and decreases the chemical hardness of the solid.…”

Section: Introductionmentioning

confidence: 99%

Study of NiMoS mixed phase from catalyst precursors in residue slurry-bed hydrocracking

Du¹,

Deng²,

Li³

et al. 2017

AIP Conference Proceedings

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Abstract. The evolution and role of NiMoS structures from catalyst precursors on residue hydrocracking was investigated. NiMoS mixed phase played important roles in unsupported catalyst and heavy oil development, such as synergy effect and coke inhibiting. The oil-soluble molybdenum naphthenate and nickel naphthenate were chosen as catalyst precursors. The mixtures of the precursor were compared to those of other monometallic oil-soluble precursor in an effort to evaluate the evolution and role of NiMoS phase in the slurry bed hydrocracking of heavy oil. The presence of NiMoS phase were characterized by X-ray diffraction (XRD), TEM and XPS. The series of tests in the slurry-phase reactor was to confirm the synergy effect of NiMoS mixed phase.

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Adsorption and dissociation of H2 and H2S on MoS2 and NiMoS catalysts

Cited by 105 publications

References 28 publications

CO hydrogenation reaction on sulfided molybdenum catalysts

CO hydrogenation reaction on sulfided molybdenum catalysts

Nucleation mechanism during WS2 plasma enhanced atomic layer deposition on amorphous Al2O3 and sapphire substrates

Study of NiMoS mixed phase from catalyst precursors in residue slurry-bed hydrocracking

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