Intrazeolite nanocomposite catalysts: Co-Mo Sulfides for Hydrodesulfurization

Okamoto, Yasuaki; Katsuyama, Hiromoto

doi:10.1002/aic.690431328

Cited by 21 publications

(11 citation statements)

References 36 publications

(53 reference statements)

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“…These results suggest that the HYD of butadiene occurs on the Co sites of the Co _ Mo binary sulfide catalyst at Co/Mo = 1 and that the Co sites are important in the HDS reaction. In agreement with the catalytic results, the Fourier transform infrared (FTIR) spectra of NO adsorption on CoSx _ MoSx/NaY 79), 96) showed that NO molecules are adsorbed exclusively on Co sites, forming dinitrosyl species, in spite of the presence of the equal amounts of Co and Mo atoms in the zeolite (2Co + 2Mo/SC). These findings suggest the formation of Co _ Mo mixed sulfides in the zeolite pores rather than a physical mixture of highly dispersed Co and Mo sulfide clusters.…”

Section: Intrazeolite Co-mo Sulfide Clusterssupporting

confidence: 71%

“…The catalytic activity of MoSx/NaY for the HDS of thiophene was 3-4 times greater than that of MoS2/ NaY 72), 78) . The activity of MoSx/NaY linearly increased up to 2Mo/SC as the Mo loading increased, followed by a more gradual increase with further addition of Mo 72),78), 96) . This suggests that the same Mo sulfide dimer species are prepared using Mo(CO)6 regardless of the number of Mo(CO)6 molecules in the supercage, if the Mo content is lower than 2Mo/SC.…”

Section: Intrazeolite Mo Sulfide Clustersmentioning

confidence: 94%

“…The activity of MoSx/NaY for the HYD of butadiene slightly decreased as the Co content in CoSx _ MoSx/NaY increased to Co/Mo = 1, followed by a steep decrease with further incorporation of Co 79), 96) . The selectivity shifted from trans-2-butene-rich to 1-butene-rich compositions with the addition of Co.…”

Section: Intrazeolite Co-mo Sulfide Clustersmentioning

confidence: 96%

“…Co _ Mo binary sulfide catalysts were prepared by introducing Co(CO)3NO into MoSx/NaY (2Mo/SC), followed by a second sulfidation at 673 K 79),85), 96) . Figure 3 shows the HDS activity of CoSx _ MoSx/NaY (2.1Mo/SC) as a function of Co content 79), 96) . The HDS activity increased as the Co/Mo ratio increased to about unity, but decreased with the further addition of Co.…”

Section: Intrazeolite Co-mo Sulfide Clustersmentioning

confidence: 99%

“…The formation of Co _ Mo binary sulfide clusters in the Co _ Mo binary sulfide catalyst was examined by XPS 79),85), 96) . 105) .…”

Section: Intrazeolite Co-mo Sulfide Clustersmentioning

confidence: 99%

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Preparation and Characterization of Co-Mo Model Sulfide Catalysts for Hydrodesulfurization

Okamoto

2003

J. Jpn. Petrol. Inst.

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Development of highly active hydrodesulfurization (HDS) catalysts is one of the most urgent problems in the petroleum industry. Better characterization and understanding of the nature of HDS catalysts on the molecular scale are of great importance for the rational design of highly active HDS catalysts. Our approaches for this purpose involve the fabrication of model catalysts using metal carbonyls to overcome the difficulties caused by the heterogeneity of practical catalysts. One of our new approaches uses the synthesis of intrazeolite homogeneous Mo, Co and Co _ Mo sulfide clusters with well defined structures. The local structure of intrazeolite Mo sulfide dimer clusters, Mo2S4, depends on the composition of the host zeolite. Thermally stabilized Co2Mo2S6 binary sulfide clusters, which show catalytic synergies between Co and Mo for thiophene HDS, with a thiocubane type structure are formed in zeolite. The intrinsic HDS activity of Co sulfide clusters depends on the host zeolite. The hydrode-selenium reaction of selenophene, combined with an extended X-ray absorption fine structure (EXAFS) study, over Mo2S4 and MoS2 clusters suggests a microscopic HDS reaction mechanism. More practical modeling of Co _ Mo sulfide catalysts using a selective preparation method of CoMoS phases supported on refractory oxides is established to understand the nature of practical HDS catalysts. No effects of the support are found with the CoMoS phase supported on Al2O3, TiO2 and ZrO2, whereas the CoMoS phase supported on SiO2 shows a higher intrinsic activity. The fraction of the CoMoS phase accessible to NO adsorption is elucidated, based on the number of the CoMoS phase in the model catalyst, suggesting a new model of the CoMoS structure. The maximum potential HDS activity of Co(Ni) _ Mo(W) catalysts is evaluated by using Co(CO)3NO as a probe molecule. Such model catalysts provide important information about the effects of the catalyst preparation and additives, the catalyst structure and the fundamental aspects of HDS catalysts such as microscopic reaction mechanisms and structure-reactivity relationship.

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Section: Intrazeolite Co-mo Sulfide Clusterssupporting

confidence: 71%

Section: Intrazeolite Mo Sulfide Clustersmentioning

confidence: 94%

Section: Intrazeolite Co-mo Sulfide Clustersmentioning

confidence: 96%

Section: Intrazeolite Co-mo Sulfide Clustersmentioning

confidence: 99%

“…The formation of Co _ Mo binary sulfide clusters in the Co _ Mo binary sulfide catalyst was examined by XPS 79),85), 96) . 105) .…”

Section: Intrazeolite Co-mo Sulfide Clustersmentioning

confidence: 99%