Effect of phosphorus addition on unsupported Ni–Mo–W sulfide catalysts prepared by the in situ activation of nickel/tetramethylammonium thiomolybdotungstate

Nava, Hildeberto; Espino, J.; Berhault, Gilles; Alonso-Núñez, G.

doi:10.1016/j.apcata.2005.12.025

Cited by 26 publications

(12 citation statements)

References 39 publications

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“…42 Previous studies have also shown that bending of the layers led to higher (110)/(100) intensity ratios than expected from a perfectly crystalline bulk sample (I(110)/I(100) = 0.52). 26,43 The actual I(110)/I(100) ratio (0.60) is slightly higher than the expected value for highly crystalline bulk MoS 2 suggesting that bending of the layers occurs either from a minor proportion of very bent slabs or from a large proportion of slabs but with small bending angles.…”

Section: Characterization By N 2 Adsorption Xrd Xps and (Hr)temmentioning

confidence: 90%

HRTEM and molecular modeling of the MoS₂–Co₉S₈interface: understanding the promotion effect in bulk HDS catalysts

Ramos

Berhault

Ferrer

et al. 2012

Catal. Sci. Technol.

144

101

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As environmental regulations increase, more selective transition metal sulfide (TMS) catalytic materials for hydrotreating applications are needed. Highly active TMS catalysts become more and more desirable triggering new interest for unsupported Co-promoted MoS 2 -based systems that have high volumetric activity as reported here. Contrary to the common observation for alumina-supported MoS 2 -based catalysts, we found in our previous studies with dibenzothiophene (DBT) hydrodesulfurization (HDS) that the catalytic activity is directly proportional to the increase of surface area of the sulfide phases (Co 9 S 8 and MoS 2 ) present in Co-promoted MoS 2 unsupported catalysts. This suggests that activity is directly connected with an increase of the contact surface area between the two sulfide phases. Understanding of the nature of the possible interaction between MoS 2 and Co 9 S 8 in unsupported catalytic systems is therefore critical in order to get a more generalized overview of the causes for synergy. This has been achieved herein through the detailed characterization by XRD, XPS, and HRTEM of the highly active Co 9 S 8 / MoS 2 catalyst resulting in a proposed model for a Co 9 S 8 /MoS 2 interface. This model was then subjected to a DFT analysis to determine a reasonable description of the surface contact region between the two bulk phases. Modelling of the interface shows the creation of open latent vacancy sites on Mo atoms interacting with Co and formation of direct Co-Mo bonds. Strong electron donation from Co to Mo also occurs through the intermediate sulfur atom bonded to both metals while an enhanced metallic character is also found. These changes in coordination and electronic properties are expected to favor a synergetic effect between Co and Mo at the proposed localized interface region between the two bulk MoS 2 and Co 9 S 8 phases.

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Section: Characterization By N 2 Adsorption Xrd Xps and (Hr)temmentioning

confidence: 90%

HRTEM and molecular modeling of the MoS₂–Co₉S₈interface: understanding the promotion effect in bulk HDS catalysts

Ramos

Berhault

Ferrer

et al. 2012

Catal. Sci. Technol.

144

101

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“…The conventional highly dispersed catalysts, water‐ and oil‐soluble catalysts, transformed into mainly micron‐sized transition metal sulfide particles that have catalytic activity for residue hydrocracking . Recently, the synthesis and application of transition metal sulfide nanoparticles for residue hydrocracking has been studied intensely . The high ratio of surface atoms of nanomaterials is the reason for their high catalytic performances .…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8][9][10] Recently, the synthesis and application of transition metal sulfide nanoparticles for residue hydrocracking has been studied intensely. [1,2,[11][12][13][14][15] The high ratio of surfacea toms of nanomaterials is the reasonf or their high catalytic performances. [16] Moreover, because of the high cost of Mo, several inexpensive transition metals,s uch as Ni, Co, and W, have been used to synthesize dispersed catalysts.…”

Section: Introductionmentioning

confidence: 99%

Surface Modification of Nickel Sulfide Nanoparticles: Towards Stable Ultra‐Dispersed Nanocatalysts for Residue Hydrocracking

Liu

et al. 2016

ChemCatChem

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Ultra‐small nickel sulfide nanoparticles (NSNPs) of 5–8 nm are prepared by a reverse microemulsion route and then modified by oleic acid and 1‐dodecanethiol to replace the adsorbed surfactant. Experimental results reveal that the particle size and crystal structure of the NSNPs did not change significantly during the modification process. Different from the adsorption by the electrostatic attraction between the surfactant and NSNPs, oleic acid and 1‐dodecanethiol are adsorbed firmly on the NSNPs through chemisorption. Catalytic hydrocracking tests demonstrate that the surface modification enhances the hydrocracking activity of the NSNPs. The surfactant‐coated NSNPs disperse in toluene‐insoluble products in as agglomerates of 20–30 nm, whereas the modified NSNPs mainly disperse as their original size. The results prove that the chemisorption of oleic acid and 1‐dodecanethiol on NSNPs remains steady and maintains the stable dispersion of NSNPs under high temperature and pressure.

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“…Ammonium thiometallates (mainly thiomolybdates and thiotungstates) are well known precursors for Mo and W disulfide catalysts used in hydrodesulfurization and hydrodenitrogenation processes [7][8][9][10]. One major achievement would be to reach an electronic structural understanding toward the nature of these chemical activities [11,12].…”

mentioning

confidence: 99%

Synthesis and Characterization of Hexamethylenediammonium Thiometallates as Precursors of MoS2 and WS2 Catalysts: In situ Activation During HDS of DBT

et al. 2009

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Hexamethylenediammonium thiometallate (HeDaT) of molybdenum and tungsten were synthesized using the aqueous solution method. This method improved significantly the yield of the catalysts. The HeDaT precursors were in situ activated during the hydrodesulfurization (HDS) of dibenzothiophene (DBT) generating MoS 2 and WS 2 catalysts. To characterize the precursors Fourier Transform Infra Red (FTIR), Ultraviolet (UV-Vis) and Nuclear Magnetic Resonance ( 1 H NMR) spectroscopy techniques were used to determine their chemical structures. In addition, thermal analysis (TGA-DTA) were performed to study the fragmentation and decomposition behavior of their molecular structures. Catalysts were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) which showed the shapes of the particles and the characteristic fringes of the layered MoS 2 and WS 2 phases, respectively. Specific surface areas were determined by the BET method with values of 5 and 19 m 2 /g with type I and IV adsorption-desorption nitrogen isotherms for both catalysts. The X-ray diffraction study showed poorly crystalline catalysts with weak (002) intensity for the MoS 2 and a better-defined (002) reflection for the WS 2 .

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Effect of phosphorus addition on unsupported Ni–Mo–W sulfide catalysts prepared by the in situ activation of nickel/tetramethylammonium thiomolybdotungstate

Cited by 26 publications

References 39 publications

HRTEM and molecular modeling of the MoS₂–Co₉S₈interface: understanding the promotion effect in bulk HDS catalysts

HRTEM and molecular modeling of the MoS₂–Co₉S₈interface: understanding the promotion effect in bulk HDS catalysts

Surface Modification of Nickel Sulfide Nanoparticles: Towards Stable Ultra‐Dispersed Nanocatalysts for Residue Hydrocracking

Synthesis and Characterization of Hexamethylenediammonium Thiometallates as Precursors of MoS2 and WS2 Catalysts: In situ Activation During HDS of DBT

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Effect of phosphorus addition on unsupported Ni–Mo–W sulfide catalysts prepared by the in situ activation of nickel/tetramethylammonium thiomolybdotungstate

Cited by 26 publications

References 39 publications

HRTEM and molecular modeling of the MoS2–Co9S8interface: understanding the promotion effect in bulk HDS catalysts

HRTEM and molecular modeling of the MoS2–Co9S8interface: understanding the promotion effect in bulk HDS catalysts

Surface Modification of Nickel Sulfide Nanoparticles: Towards Stable Ultra‐Dispersed Nanocatalysts for Residue Hydrocracking

Synthesis and Characterization of Hexamethylenediammonium Thiometallates as Precursors of MoS2 and WS2 Catalysts: In situ Activation During HDS of DBT

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HRTEM and molecular modeling of the MoS₂–Co₉S₈interface: understanding the promotion effect in bulk HDS catalysts

HRTEM and molecular modeling of the MoS₂–Co₉S₈interface: understanding the promotion effect in bulk HDS catalysts