Characterization and HDS Activity of Mesoporous MoS2 Catalysts Prepared by in Situ Activation of Tetraalkylammonium Thiomolybdates

Alonso, Gabriel Gutiérrez; Berhault, Gilles; Aguilar, A.; Collins, Virginia; Ornelas, C.; Fuentes, S.; Chianelli, Russell R.

doi:10.1006/jcat.2002.3553

Cited by 124 publications

(83 citation statements)

References 31 publications

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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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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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“…A confinement effect [17] is obvious comparing MoS 2 catalysts supported on 6 nm and 9 nm SBA-15: a significant enhancement of the hydrogenation reactivity is observed for MoS 2 supported on SBA-15 with the larger diameter of about 9 nm (S HYD /S DDS = 1.57, 11 wt.% Mo, see Fig. 7), despite the lower Mo loading compared to the catalyst supported on 6 nm material (16 wt.% Mo; S HYD / S DDS = 1.43).…”

Section: Catalytic Hds Activity and Selectivitymentioning

confidence: 99%

“…It was observed that the thermal decomposition of molybdenum and tungsten thiosalts is an effective method for the production of improved unsupported catalysts. One reason is that no metal-sulfur bond formation is required which is necessary applying the oxide route [16][17][18][19]. However, to the best of our knowledge only a few studies have been performed to investigate supported MoS 2 catalysts derived from ammonium thiomolybdate (ATM) as precursor [20,21].…”

Section: Introductionmentioning

confidence: 99%

SBA-15 as Support for MoS2 and Co-MoS2 Catalysts Derived from Thiomolybdate Complexes in the Reaction of HDS of DBT

et al. 2007

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Molybdenum sulfide and cobalt-molybdenum sulfide catalysts supported on mesoporous SBA-15 were prepared by thermal decomposition of ammonium thiomolybdate (ATM). SBA-15 was synthesized at 353 K and 413 K to obtain pore diameters of about 6 and 9 nm, respectively. The (Co)-MoS 2 /SBA-15 catalysts were characterized with X-ray diffraction (XRD), N 2 -physisorption and high-resolution transmission electron microscopy (HRTEM). HRTEM images give evidence for the presence of a poorly dispersed MoS 2 phase with long MoS 2 slabs and a pronounced MoS 2 stacking. The catalytic performance in the hydrodesulfurization (HDS) reaction of dibenzothiophene (DBT) was examined at T = 623 K and P = 3.4 MPa. The Co-MoS 2 /SBA-15 materials show a relatively high catalytic activity with a strong preference for the direct desulfurization (DDS) pathway. This is an interesting result in view of the significant stacking of MoS 2 particles and the size of the slabs. The generation of the catalytically active CoMoS phase and a large number of coordinately unsaturated sites (CUS) may explain the high performance of Co promoted MoS 2 /SBA-15 catalysts in the HDS reaction.A confinement effect of the mesoporous channels of SBA-15 is observed for the unpromoted MoS 2 /SBA-15 catalysts. SBA-15 with 9 nm channel diameter with 11 wt.% Mo loading shows a higher selectivity for the hydrogenation pathway than SBA-15 with 6 nm channel and 16 wt.% Mo loading.

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“…HDS is the central process to remove sulphur from crude oils. There are several ways to prepare these catalysts, like comaceration [29], homogeneous sulphide precipitation [14], hydrothermal and solvothermal processes [30][31][32][33][34], solution reactions [35,36] and thiosalt decomposition [37][38][39]. With the decomposition of thiotungstates a high sulphur content can be achieved in the final WS 2 catalysts [40,41].…”

Section: Ws 2 Catalysts Are Promoted Mostly With Cobalt or Nickel Andmentioning

confidence: 99%

“…The thermal behaviour of different tetraalkylammonium thiotungstates was investigated previously in detail [7,9,10,15,16,39,[46][47][48], but in case of the ATT only some studies can be found [5,49,50]. In 1970 Voorhoeve et al [49] investigated the decomposition of ATT in vacuum and H 2 flow by X-ray diffraction (XRD), differential thermal analysis (DTA), optical microscopy and electron spin resonance (ESR).…”

Section: Ws 2 Catalysts Are Promoted Mostly With Cobalt or Nickel Andmentioning

confidence: 99%

Thermal decomposition of ammonium tetrathiotungstate

Hunyadi

Ramos

Szilágyi

2015

J Therm Anal Calorim

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The thermal decomposition of ammonium tetrathiotungstate (ATT), (NH 4 ) 2 WS 4 was studied by SEM, FTIR, XRD, EDX and TG/DTA-MS. The decomposition of ATT involved three steps in inert atmosphere: (i) release of free water between 30-140 °C; (ii) formation of an amorphous WS 3 phase between 170-280 °C, from which (iii) a slightly crystalline WS 2 formed between 330-470 °C. As a difference compared to inert atmosphere, in air in the second step the ATT decomposed into directly WS 2 instead of WS 3 . This WS 2 phase was amorphous, and still contained traces of ATT. Between 260-2 500 °C from the WS 2 monoclinic tungsten oxide crystallized in two steps: at 302 °C a slightly crystalline m-WO 3 formed, which became more crystalline at 471 °C. During the investigation of the effect of the particle size, it was found that the thermal behaviour of ATT crystals was similar to ATT powder, with some shift in the decomposition temperature. The XRD results showed that the WS 2 formed from the ATT powder in N 2 had a higher level of crystallization, compared to the WS 2 obtained from ATT crystals.

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Characterization and HDS Activity of Mesoporous MoS2 Catalysts Prepared by in Situ Activation of Tetraalkylammonium Thiomolybdates

Cited by 124 publications

References 31 publications

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

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

SBA-15 as Support for MoS2 and Co-MoS2 Catalysts Derived from Thiomolybdate Complexes in the Reaction of HDS of DBT

Thermal decomposition of ammonium tetrathiotungstate

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