Transmission electron microscopy of catalysts

Sanders, J. V.

doi:10.1002/jemt.1060030108

Cited by 42 publications

(11 citation statements)

References 68 publications

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“…The experimental pattern also shows the concentric rings of diffuse intensity concentrations originating from the MoS 2 slabs surrounding the crystal (see the arrow highlighting the circle with diameter d(002) * 6.2 Å ). Inhomogeneous nanostructures based on a core and MoS 2 shells were frequently observed in the past, even for NiS-MoS 2 core-shell particles [28,29]. Recently, Ni sulfide segregation decorated with MoS 2 layers were also observed in Type 1/2 Ni-Mo catalysts by TEM [19].…”

Section: Transmission Electron Microscopymentioning

confidence: 90%

SBA-15 as Support for Ni–MoS2 HDS Catalysts Derived from Sulfur-containing Molybdenum and Nickel Complexes in the Reaction of HDS of DBT: An All Sulfide Route

et al. 2008

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MoS 2 HDS catalysts promoted with Ni supported on SBA-15 were synthesized from sulfur containing Mo (ammonium thiomolybdate, ATM, and tetramethylammonium thiomolybdate, TMATM) and a Ni complex (Nickel diethylthiocarbamate, NiDETC). The catalysts have been characterized by X-ray diffraction (XRD), N 2 -physisorption and High-resolution transmission electron microscopy (HRTEM). The catalytic performance in the hydrodesulfurization (HDS) reaction of dibenzothiophene (DBT) was examined at T = 623 K and P H2 = 3.4 Mpa. In comparison with the impregnation mode, the nature of the employed thiomolybdate complex shows a stronger influence on the MoS 2 morphology and consequently on the HDS activity of DBT. A similar high HDS activity to a commercial NiMo/c-Al 2 O 3 catalyst despite the pronounced stacking number is shown for a NiMoS 2 /SBA-15 catalyst derived from ATM. The catalysts derived from TMATM showed lower HDS activities compared to the catalysts obtained from ATM precursors due to probably the presence of closed shell structures (nano-onions) of MoS 2 which offer significantly smaller amount of HDS active sites (edge sites). Moreover, the HYD/DDS ratios are interestingly higher with respect to the HYD/DDS ratio of the commercial NiMo/c-Al 2 O 3 catalyst which could be ascribed to the generation of multilayered MoS 2 active phase.

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Section: Transmission Electron Microscopymentioning

confidence: 90%

SBA-15 as Support for Ni–MoS2 HDS Catalysts Derived from Sulfur-containing Molybdenum and Nickel Complexes in the Reaction of HDS of DBT: An All Sulfide Route

et al. 2008

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“…According to reported estimates, less than 10% of alumina-supported MoS 2 nanoparticles are visualized by HRTEM that is not a representative part. 17,37,38 In contrast, the XRD patterns contain averaged information from whole volume of powder samples.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Total Scattering Debye Function Analysis: Effective Approach for Structural Studies of Supported MoS₂-Based Hydrotreating Catalysts

Pakharukova

Yatsenko

Gerasimov

et al. 2020

Ind. Eng. Chem. Res.

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High dispersion and low degree of crystallinity of supported MoS2 nanoparticles have almost excluded the conventional X-ray diffraction (XRD) analysis from a range of physical methods for the characterization of molybdenum-based hydrotreating catalysts. High-resolution transmission electron microscopy (HRTEM) remains a powerful and preferred technique for obtaining information on the dispersion of supported MoS2 nanoparticles and stacking degree of MoS2 slabs. Here, we report a new approach to study the supported MoS2 nanoparticles in catalysts on the basis of XRD data. Alumina-supported MoS2 catalysts were investigated by means of the Debye function analysis (DFA) applied to the XRD data obtained using the conventional laboratory equipment. Through a direct simulation of XRD profiles by the DFA technique, structural information is extracted from both Bragg and diffuse scattering. We demonstrate that it is possible to determine the average size of coherently scattering MoS2 crystallites, crystallite size distribution, as well as average number of stacked layers in the MoS2 particles from the XRD data. Compared to the widely used HRTEM study, the DFA analysis underestimates the MoS2 particle size due to structural defects. The significant discrepancy between the XRD and HRTEM data serves as an indicator of abundant defects causing a multidomain structure of MoS2 particles. It is shown that HRTEM and XRD data complement each other by providing information on the MoS2 dispersion at different levels of particle organization.

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“…Inspired by the analogy between graphite and inorganic layered compounds and the discovery of closed-cage carbon nanoparticles (NPs), Tenne et al proposed in 1992 that such inorganic layered compounds will suffer the same kind of instability and form closed-cage nanostructures. , Here, the extra stored energy in the rim atoms leads to their folding and seaming into closed-cage (hollow) nanostructures, which were designated as inorganic fullerene-like nanoparticles (IFs) and inorganic nanotubes (INTs). Prior to the above work, several publications reporting rolled MoS 2 sheets analogous to nanoscrolls or closed-shell MoS 2 NPs appeared in the literature. However, no systematic investigation of these nanostructures was pursued any further in the ensuing years.…”

Section: Prefacementioning

confidence: 99%

Inorganic Nanotubes and Fullerene-like Nanoparticles at the Crossroads between Solid-State Chemistry and Nanotechnology

2017

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Inorganic nanotubes (NTs) and fullerene-like nanoparticles (NPs) of WS were discovered some 25 years ago and are produced now on a commercial scale for various applications. This Perspective provides a brief description of recent progress in this scientific discipline. The conceptual evolution leading to the discovery of these NTs and NPs is briefly discussed. Subsequently, recent progress in the synthesis of such NPs from a variety of inorganic compounds with layered (2D) structure is described. In particular, we discuss the synthesis of NTs from chalcogenide- and oxide-based ternary misfit layered compounds, as well as their structure and different growth mechanisms. Next we deliberate on the mechanical, optical, electrical, and electromechanical properties, which delineate them from their bulk counterparts and also from their graphene-like analogues. Here, different experiments with individual NTs coupled with first-principles and molecular dynamics calculations demonstrate the unique physical nature of these quasi-1D nanostructures. Finally, the various applications of the fullerene-like NPs of WS and NTs formed therefrom are deliberated. Foremost among the possibilities are their extensive uses as superior solid lubricants. Combined with their nontoxicity and their facile dispersion, these NTs, with an ultimate strength of about 20 GPa, are likely to find numerous applications in reinforcing polymers, adhesives, textiles, medical devices, metallic alloys, and even concrete. Other potential applications in energy-harvesting and catalysis are discussed in brief.

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Transmission electron microscopy of catalysts

Cited by 42 publications

References 68 publications

SBA-15 as Support for Ni–MoS2 HDS Catalysts Derived from Sulfur-containing Molybdenum and Nickel Complexes in the Reaction of HDS of DBT: An All Sulfide Route

SBA-15 as Support for Ni–MoS2 HDS Catalysts Derived from Sulfur-containing Molybdenum and Nickel Complexes in the Reaction of HDS of DBT: An All Sulfide Route

Total Scattering Debye Function Analysis: Effective Approach for Structural Studies of Supported MoS₂-Based Hydrotreating Catalysts

Inorganic Nanotubes and Fullerene-like Nanoparticles at the Crossroads between Solid-State Chemistry and Nanotechnology

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Transmission electron microscopy of catalysts

Cited by 42 publications

References 68 publications

SBA-15 as Support for Ni–MoS2 HDS Catalysts Derived from Sulfur-containing Molybdenum and Nickel Complexes in the Reaction of HDS of DBT: An All Sulfide Route

SBA-15 as Support for Ni–MoS2 HDS Catalysts Derived from Sulfur-containing Molybdenum and Nickel Complexes in the Reaction of HDS of DBT: An All Sulfide Route

Total Scattering Debye Function Analysis: Effective Approach for Structural Studies of Supported MoS2-Based Hydrotreating Catalysts

Inorganic Nanotubes and Fullerene-like Nanoparticles at the Crossroads between Solid-State Chemistry and Nanotechnology

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Total Scattering Debye Function Analysis: Effective Approach for Structural Studies of Supported MoS₂-Based Hydrotreating Catalysts