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Nava, Hildeberto; Ornelas, C.; Aguilar, A.; Berhault, Gilles; Fuentes, S.; Alonso, Gabriel Gutiérrez

doi:10.1023/a:1022632505797

Cited by 52 publications

(45 citation statements)

References 28 publications

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“…Even for NiMoW-H catalyst, a certain amount of carbon is detected even though no carbon is present on the precursor salt. This result is observed previously for Co-promoted MoS 2 under the same conditions (C/Mo=2.2) [12]. The amount of carbon increases as long as the carbon atoms increase on the alkyl chain.…”

Section: Elemental Analysissupporting

confidence: 89%

“…The materials obtained using this procedure presents interesting morphological properties with high specific area and characteristic type IV isotherms with a sharp mesoporous distribution and the presence of various active phases. A hydrogenative effect of Ni is observed and an enhanced HDS activity compared with other Mo systems supported or unsupported (commercial NiMo/Al 2 O 3 k ¼ 12 Â 10 À7 mol/g*s, CoMo k ¼ 17:4 Â 10 À7 mol/g*s) [12].…”

Section: Discussionmentioning

confidence: 90%

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Nickel-Molybdenum-Tungsten Sulfide catalysts prepared by in situ activation of tri-metallic (Ni-Mo-W) alkylthiomolybdotungstates

2005

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Unsupported nickel-molybdenum-tungsten sulphide catalysts were prepared from tri-metallic Ni-Mo-W alkyl precursors by in situ activation during the hydrodesulphurization (HDS) of dibenzothiophene (DBT). The tri-metallic Ni-Mo-W precursors were prepared by reaction of tetraalkylammonium thiomolibdotungstates salts, (R 4 N) 4 MoWS 8 (where R = H, methyl, propyl, butyl, cetyl-trimetyl), with NiCl 2 in water at a Ni/Mo(W) molar ratio of 2. These precursors are named Ni/(NH 4 ) C 1 , NiMoW-C 3 , NiMoW-C 4 and NiMoW-C C catalysts respectively. These catalysts exhibit a ''Swiss-cheese''-like morphology, a wide distribution of specific areas (from 46.9-194.07 m 2 /g) and high content of carbon (C/Mo = 2.5-8.9). The in situ activation of these tetraalkylammonium thiotrimetallates precursors leads to a mesoporous structure with pore size ranging from 10-40 Å and type IV adsorption-desorption isotherms of nitrogen. X-ray diffraction showed that the structure of unsupported nickelmolybdenum-tungsten sulphide catalysts corresponds to a typical structure of 2H-MoS 2 poorly crystalline with low-stacked layers. The nature of the alkyl group strongly affects both the specific area and the HDS activity. The catalytic activity is strongly enhanced when using carbon-containing precursors; the NiMoW catalysts prepared by in situ activation present high HDS activity. The lowest specific area of the catalysts was observed for the NiMoW-H sample.

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Section: Elemental Analysissupporting

confidence: 89%

Section: Discussionmentioning

confidence: 90%

Nickel-Molybdenum-Tungsten Sulfide catalysts prepared by in situ activation of tri-metallic (Ni-Mo-W) alkylthiomolybdotungstates

2005

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“…The other catalysts have relatively poor surface areas ranging from 2 to 27 m 2 /g (table 2). These results suggest the effect of carbon support combined with the synergistic effect of nickel being at the optimum in C3Mo035, as previously observed when tetrabutylammonium thiometalate is used as a precursor combined with a cobalt promoter [37].…”

Section: Catalysts From Mixtures Of Ndta-tm and Tpa-tmsupporting

confidence: 82%

High activity Ni/MoS2 catalysts obtained from alkylthiometalate mixtures for the hydrodesulfurization of dibenzothiophene

et al. 2007

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An efficient method for improving the catalytic properties of unsupported Ni/MoS 2 catalysts is mixing thiometalate precursors applying the appropriate precursors and thermal conditions. High active catalysts for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) are prepared by the controlled decomposition of physical mixtures of Ni(diethylentriamine) 2 MoS 4 (NDTA-TM) and [(Propyl) 4 N)] 2 MoS 4 (TPA-TM). The catalysts with a higher content of NDTA-TM are very active with a high selectivity for the direct desulfurization pathway (DDS) due to the synergistic effect of nickel. In addition the presence of a large amount of carbon may produce single-slabs of nickel promoted carbon containing molybdenum sulfides. The activity enhancement is attributed to an increased number of NiMoS active sites originated by the chemical interaction between the precursors NDTA-TM and TPA-TM during the mixing procedure. Furthermore, the carbon content in the final products is related to the enhancement of the activity and the preference of the DDS pathway. The controlled decomposition of mixtures of NDTA-TM + TPA-TM yields catalysts which are about twofold more active than an industrial NiMo/Al 2 O 3 catalyst. This improvement may be attributed to an intense interaction of the precursors during the synthesis causing a re-dispersion of nickel atoms from NDTA-TM over the surface of carbon containing molybdenum sulfide provided by the precursor TPA-TM, increasing the amount of active sites. The catalysts from mixtures of (NH 4 ) 2 MoS 4 (A-TM) and NDTA-TM behave similarly to the pure precursors.

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“…Using Mo precursors containing alkyl groups instead of the small ammonium ion yield a new type of sulfide materials during the thermal decomposition which could be called ''amorphous mesoporous sulfide'' catalysts with a remarkable increase of the HDS catalytic activity [20,23,24]. Recently, the decomposition of ATM was successfully applied for the preparation of catalysts supported on SBA-15 [12].…”

Section: Discussionmentioning

confidence: 99%

Preparation and Characterization of SBA-15 Supported Cobalt–Molybdenum Sulfide Catalysts for HDS Reaction: An All Sulfide Route to Hydrodesulfurization Catalysts

et al. 2008

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MoS 2 hydrodesulfurization (HDS) catalysts promoted with Co supported on SBA-15 were synthesized from sulfur-containing Mo sources [ammonium thiomolybdate (ATM), and tetramethylammonium thiomolybdate (TMATM)] and Co complexes cobalt dimethylthiocarbamate by using different synthesis strategies in order to achieve active catalysts. The (Co)-MoS 2 /SBA-15 catalysts were characterized with X-ray diffraction, N 2 -physisorption and High-Resolution Transmission Electron Microscopy. The catalytic performance in the HDS reaction of dibenzothiophene was examined at T = 623 K and P H2 = 3.4 MPa. The results of the experiments suggest that the sequence of impregnation steps has no significant influence on the HDS activity. On the other hand, the use of different thiomolybdate precursors significantly affects the catalytic activity. The catalysts derived from TMATM show lower HDS activities compared to the catalysts synthesized from ATM which is probably due to the presence of pronounced pore blocking as well as the generation of big needle-like aggregates of the Co-MoS 2 phase. It seems that the formation of intermediate MoS 3 is not a prerequisite for the generation of catalytic active CoMoS phases. The high activity and high selectivity for the direct desulfurization pathway of catalysts prepared with ATM despite the large MoS 2 stacking could be due to the generation of a large number of coordinately unsaturated sites.

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Cited by 52 publications

References 28 publications

Nickel-Molybdenum-Tungsten Sulfide catalysts prepared by in situ activation of tri-metallic (Ni-Mo-W) alkylthiomolybdotungstates

Nickel-Molybdenum-Tungsten Sulfide catalysts prepared by in situ activation of tri-metallic (Ni-Mo-W) alkylthiomolybdotungstates

High activity Ni/MoS2 catalysts obtained from alkylthiometalate mixtures for the hydrodesulfurization of dibenzothiophene

Preparation and Characterization of SBA-15 Supported Cobalt–Molybdenum Sulfide Catalysts for HDS Reaction: An All Sulfide Route to Hydrodesulfurization Catalysts

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