Transition Metal Sulfide Catalysts for Petroleum Upgrading – Hydrodesulfurization Reactions

Infantes‐Molina, Antonia; Romero-Pérez, A.; Eliche-Quesada, D.; Mérida‐Robles, J.; Jiménez-López, A.; Castellón, Enrique Rodríguez

doi:10.5772/45629

Cited by 6 publications

(3 citation statements)

References 51 publications

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“…Current environmental protection laws require desulfurization of petroleum. Transition-metal-supported molybdenum and tungsten chalcogenide catalysts facilitate an efficient desulfurization reaction via chalcogenide surface defects . N 2 reduction, which is critical to industrial chemical engineering processes, can be efficiently achieved at transition-metal-passivated defect sites on WS 2 .…”

Section: Resultsmentioning

confidence: 99%

Origins of Fermi Level Pinning between Tungsten Dichalcogenides (WS₂, WTe₂) and Bulk Metal Contacts: Interface Chemistry and Band Alignment

et al. 2020

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Thin metal films (Au, Ir, Cr, and Sc), deposited by an electron beam on bulk, exfoliated WS2 and WTe2 using two different reactor base pressures (high vacuum (HV) <2 × 10–6 mbar; ultrahigh vacuum (UHV) <2 × 10–9 mbar), are explored to study the effects of reactor ambient on the interface chemistry formed at room temperature between bulk metal contacts and tungsten dichalcogenides (TDCs). Au forms a van der Waals interface with WS2 and a covalent interface with WTe2, independent of reactor ambient. In contrast, an intermetallic is detected at the Ir–WS2 and Ir–WTe2 interfaces regardless of the reactor ambient. The low work function metals Cr and Sc, which are more reactive than their high work function counterparts (Au and Ir), completely reduce the TDC layer(s) in direct contact. Sc is completely oxidized in situ when deposited in an elastomer-sealed deposition tool (in HV). These results highlight that the interface between metals and TDCs is most often covalent, which contrasts the common misconception that a van der Waals gap is present. Furthermore, the band alignment between the four metals investigated here and bulk WS2 deviates significantly from that predicted by the Schottky–Mott rule. These results elucidate the true chemistry of select metal–TDC interfaces and highlight the rapid oxidation that manifests in situ in a HV metallization environment. Our work emphasizes the need to consider the true interface chemistry when engineering and modeling metal contacts to WS2 and WTe2.

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Section: Resultsmentioning

confidence: 99%

Origins of Fermi Level Pinning between Tungsten Dichalcogenides (WS₂, WTe₂) and Bulk Metal Contacts: Interface Chemistry and Band Alignment

et al. 2020

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“…This shows how the NiMo1-R layer, even though it presents a lower RVA than the reactivated CoMo-1R (95% vs. 99%), has a strong effect on the overall reactor performances. NiMo is known to have a higher catalytic activity against bulky organic sulfurs and nitrogen, thanks to its higher HYD pathway [4,7]. The benefit of a stacked configuration and the exact role of the NiMo layer will be discussed later.…”

Section: Resultsmentioning

confidence: 99%

“…There are two main chemical routes based on the accessibility of the sulfurs atom, from the organic reactant (''organic-sulfur''), to the active site of the catalyst. Compounds having easily accessible sulfurs typically follow a direct hydrogenolysis route (DDS), predominant with Co-promoted catalysts [7]. To remove sulfurs sterically hindered (e.g.…”

Section: Introductionmentioning

confidence: 99%

Maximizing utilization of reactivated and left-over catalysts in heavy gas oil hydrotreater: A case study of ADNOC Refining

Laveille

Chaudhry

Riva³

et al. 2018

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Recently, ADNOC Refining Research Center (ARRC) has studied the possibility to maximize the reutilization of left-overs and reactivated hydrodesulfurization catalysts for one of its hydrotreater producing Ultra Low Sulfur Diesel (ULSD) from Heavy Gas Oil (HGO). Based on the refinery inventory, several catalyst configurations composed of different amounts of reactivated and fresh CoMo catalyst, including a full reactivated configuration having a stacked CoMo/NiMo/CoMo combination (50/25/25), have been tested in a pilot-plant reactor under commercially-relevant conditions. Experimental results in terms of reactor bed temperature, H2 consumption, aromatics and diesel yields have been analyzed and compared to the current commercial hydrotreater load and catalyst supplier forecasts for the studied configurations. Results show excellent performances of reactivated catalysts and a strong effect of the NiMo layer in the case of the stacked configuration. In a pure CoMo configuration, up to 75% reactor volume of reactivated catalyst could be utilized without impacting the product quality and cycle length, compared to a full fresh CoMo catalyst load. The full reactivated stacked configuration performed even better than the full fresh CoMo catalyst, without impacting product quality and diesel yield. Potential effect of the reactivated catalysts on the reaction selectivity and the role of the NiMo layer in the stacked configuration are discussed. Pilot-plant experimental data were in strong accordance with catalyst supplier commercial forecasts, emphasizing the quality of the pilot-plant study. Implementation of one of the studied configuration by the refinery could lead to between 30% and 55% savings on the cost of catalyst for the next load.

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Computational Insights into the Mechanisms of H₂ Activation and H₂/D₂ Isotope Exchange by Dimolybdenum Tetrasulfide Complexes

Algarra

2016

Eur J Inorg Chem

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The mechanisms for H 2 activation by [Cp*Mo] 2 (μ-S) 2 (μ-S 2) (1-a, Cp* = pentamethylcyclopentadienyl) and its reaction product [Cp*Mo] 2 (μ-S) 2 (μ-SH) 2 (2) have been investigated by DFT methods. The reaction of 1-a involves the homolytic addition of H 2 to its μ-S ligands, followed by the cleavage of the S-S bond of the μ-S 2 ligand in a subsequent step. Complex 2 can adopt five conformations that only differ in the stereochemistry of the μ-SH and μ-S ligands; although an isomer with adjacent μ-S ligands (2-a) is formed initially, it then isomerises

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Transition Metal Sulfide Catalysts for Petroleum Upgrading – Hydrodesulfurization Reactions

Cited by 6 publications

References 51 publications

Origins of Fermi Level Pinning between Tungsten Dichalcogenides (WS₂, WTe₂) and Bulk Metal Contacts: Interface Chemistry and Band Alignment

Origins of Fermi Level Pinning between Tungsten Dichalcogenides (WS₂, WTe₂) and Bulk Metal Contacts: Interface Chemistry and Band Alignment

Maximizing utilization of reactivated and left-over catalysts in heavy gas oil hydrotreater: A case study of ADNOC Refining

Computational Insights into the Mechanisms of H₂ Activation and H₂/D₂ Isotope Exchange by Dimolybdenum Tetrasulfide Complexes

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Transition Metal Sulfide Catalysts for Petroleum Upgrading – Hydrodesulfurization Reactions

Cited by 6 publications

References 51 publications

Origins of Fermi Level Pinning between Tungsten Dichalcogenides (WS2, WTe2) and Bulk Metal Contacts: Interface Chemistry and Band Alignment

Origins of Fermi Level Pinning between Tungsten Dichalcogenides (WS2, WTe2) and Bulk Metal Contacts: Interface Chemistry and Band Alignment

Maximizing utilization of reactivated and left-over catalysts in heavy gas oil hydrotreater: A case study of ADNOC Refining

Computational Insights into the Mechanisms of H2 Activation and H2/D2 Isotope Exchange by Dimolybdenum Tetrasulfide Complexes

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Product

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Origins of Fermi Level Pinning between Tungsten Dichalcogenides (WS₂, WTe₂) and Bulk Metal Contacts: Interface Chemistry and Band Alignment

Origins of Fermi Level Pinning between Tungsten Dichalcogenides (WS₂, WTe₂) and Bulk Metal Contacts: Interface Chemistry and Band Alignment

Computational Insights into the Mechanisms of H₂ Activation and H₂/D₂ Isotope Exchange by Dimolybdenum Tetrasulfide Complexes