ChemInform Abstract: RAMAN SPECTROSCOPIC STUDY OF COBALT‐MOLYBDENUM Γ‐ALUMINA CATALYSTS

Koningsberger, D.C.; Medema, J.; Stam, C. van; Beer, V.H.J. de; Konings, A.J.A.

doi:10.1002/chin.197840043

Cited by 20 publications

(23 citation statements)

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“…% corresponds to a theoretical molybdate monolayer on the y-A1 2 0 3 support used. At decreasing loading in the submonolayer range, the surface concentration of the polymolybdate species is reduced in favor of a distorted monomeric tetrahedral MoO; -species [310,316].…”

Section: C) Raman Spectroscopymentioning

confidence: 99%

“…Supported molybdate catalysts promoted by Ni2+ [313,314] and C0 2 + [312, [315][316][317][318] have been studied by Raman spectroscopy and Sombret et al [320] have applied the Raman microscope technique to obtain information about the spatial distribution of surface species and compounds. Other supported oxide catalysts have equally successfully been characterized by their Raman spectra in the low frequency region, namely tungsten oxide on y-A1 2 0 3 [321,322], rhenium oxide on alumina [323], and vanadium oxide on alumina [324,325].…”

Section: C) Raman Spectroscopymentioning

confidence: 99%

“…The series of sharp lines observed for sample Mol2All (12 wt % Mo0 3 supported on y-A1 2 0 3 by impregnation at pH 1 and calcination 773 K) are characteristic for the formation of bulk Mo0 3 , while the broad features at 960 and 850 cm -1 are typical for an interaction species. This latter surface species was described as a two-dimensional surface polymolybdate with M0 6 + in octahedral coordination [310,311,[315][316][317][318][319]. The complete set of Raman bands of this species can be assigned as follows: 310-370 cm -1 (M=O bending), 900-1000 cm -1 (Mo=O stretching), 200-250 cm-1 (Mo-O-Mo deformation), 400-600 cm-1 (symmetric Mo-O-Mo stretching and 700-850 cm-1 (anti symmetric Mo-O-Mo stretching).…”

Section: C) Raman Spectroscopymentioning

confidence: 99%

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Nature and Estimation of Functional Groups on Solid Surfaces

Boehm

Knözinger

1983

Catalysis

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Section: C) Raman Spectroscopymentioning

confidence: 99%

Section: C) Raman Spectroscopymentioning

confidence: 99%

Section: C) Raman Spectroscopymentioning

confidence: 99%

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Nature and Estimation of Functional Groups on Solid Surfaces

Boehm

Knözinger

1983

Catalysis

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“…It has been reported that the transition metal content of the catalysts influences the relative amounts of the various species (8, 12,13,21). This is the reason why in this study the active-phase concentration has been varied to a large extent.…”

Section: Introductionmentioning

confidence: 99%

Characterization of $gamma;-alumina-supported Molybdenum oxide and tungsten oxide; reducibility of the oxidic state versus hydrodesulfurization activity of the sulfided state

Thomas

1982

Journal of Catalysis

196

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Characterization of gamma-alumina-supported molybdenum oxide and tungsten oxide : reducibility of the oxidic state versus hydrodesulfurization activity of the sulfided state Thomas Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publicationCitation for published version (APA): Thomas, R., Oers, van, E. M., Beer, de, V. H. J., Medema, J., & Moulijn, J. A. (1982). Characterization of gamma-alumina-supported molybdenum oxide and tungsten oxide : reducibility of the oxidic state versus hydrodesulfurization activity of the sulfided state. Journal of Catalysis, 76(2), 241-253. DOI: 10.1016/0021-9517%2882%2990255-X, 10.1016/0021-9517(82)90255-X General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Thiophene hydrodesulfurization and butene hydrogenation have been determined for MOO&-A1203, WOJ-y-A&OS, and RezO,/y-A&O3 catalysts, using a micro-flow reactor operating at atmospheric pressure. Catalysts have been prepared by various methods, viz., ion exchange, gas-phase adsorption, dry and wet impregnation of y-Al2O3 as well as impregnation of boehmite. The catalysts have been prepared on a surface coverage basis.The catalysts were characterized by X-ray diffraction, surface area and pore volume measurements, and temperature-programmed reduction (TPR). Moody-Al,O, and WO&-A1203 catalysts prepared by dry and wet impregnation give essentially the same results.A correlation exists between the reducibility of oxidic Moody-Al,O, and WOJy-A&O3 catalysts prepared by dry and wet impregnation, and the hydrodesulfurization activity of the sulfided samples. The higher the reducibility, the higher the hydrodesul...

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“…[37] The band around 990 cm À1 shifted towards higher wavenumbers upon increasing the calcination temperature, which could be due to a shorter Mo¼O bond and more severe structural distortion. [28,29] The increase in relative intensity indicated a higher coverage of these molybdate species.…”

mentioning

confidence: 98%

Highly Dispersed MoO₃/Al₂O₃ Shell‐Core Composites Synthesized by CVD of Mo(CO)₆ under Atmospheric Pressure

Shi

Franzke

Xia

et al. 2011

Chemical Vapor Deposition

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composites are synthesized by CVD under atmospheric pressure using Mo(CO) 6 as the precursor and porous g-Al 2 O 3 particles in a horizontal, rotating, hot-wall reactor, which is also used for calcination in air. The composites are characterized by N 2 physisorption, atomic absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and laser Raman spectroscopy (LRS). The synthesized samples exhibit excellent porosity, even at high Mo loadings. A much higher Mo yield is achieved when applying sublimation-adsorption in static air instead of using flowing N 2 . A high degree of Mo dispersion on alumina is confirmed by XRD, LRS, and TEM; with a Mo surface density as high as 5.2 atoms nm À2, the sample is X-ray amorphous, there are no polymeric molybdate species detectable by LRS, and the island size of the molybdate species is about 1 nm according to TEM. The XPS analysis shows that exclusively Mo VI species are present on all synthesized samples. Thus, the applied rotating, hot-wall reactor achieves efficient mixing and homogeneous deposition.

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ChemInform Abstract: RAMAN SPECTROSCOPIC STUDY OF COBALT‐MOLYBDENUM Γ‐ALUMINA CATALYSTS

Abstract: Die Strukturen der Mound Co‐Spezies in Co‐Mo/y‐Al,O3‐Katalysatorsystemen werden mit Hilfe der Laser‐ Raman‐Spektroskopie untersucht.

Cited by 20 publications

References 1 publication

Nature and Estimation of Functional Groups on Solid Surfaces

Nature and Estimation of Functional Groups on Solid Surfaces

Characterization of $gamma;-alumina-supported Molybdenum oxide and tungsten oxide; reducibility of the oxidic state versus hydrodesulfurization activity of the sulfided state

Highly Dispersed MoO₃/Al₂O₃ Shell‐Core Composites Synthesized by CVD of Mo(CO)₆ under Atmospheric Pressure

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ChemInform Abstract: RAMAN SPECTROSCOPIC STUDY OF COBALT‐MOLYBDENUM Γ‐ALUMINA CATALYSTS

Abstract: Die Strukturen der Mound Co‐Spezies in Co‐Mo/y‐Al,O3‐Katalysatorsystemen werden mit Hilfe der Laser‐ Raman‐Spektroskopie untersucht.

Cited by 20 publications

References 1 publication

Nature and Estimation of Functional Groups on Solid Surfaces

Nature and Estimation of Functional Groups on Solid Surfaces

Characterization of $gamma;-alumina-supported Molybdenum oxide and tungsten oxide; reducibility of the oxidic state versus hydrodesulfurization activity of the sulfided state

Highly Dispersed MoO3/Al2O3 Shell‐Core Composites Synthesized by CVD of Mo(CO)6 under Atmospheric Pressure

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Product

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About

Highly Dispersed MoO₃/Al₂O₃ Shell‐Core Composites Synthesized by CVD of Mo(CO)₆ under Atmospheric Pressure