Journal ArticleDOI
Studies on molybdena-alumina catalysts: VII. Effect of cobalt on catalyst states and reducibility
K.S. Chung,F.E. Massoth +1 more
TLDR
In this paper, the effect of cobalt on the structure and reducibility of a series of molybdena-alumina catalysts was studied, and two separate phases were found, a Co-Al2O3 interaction phase, which was nonreducible, and a well-defined Co3O4 phase which reduced to Co metal.About:
This article is published in Journal of Catalysis.The article was published on 1980-08-01. It has received 149 citations till now. The article focuses on the topics: Cobalt & Calcination.read more
Citations
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Journal ArticleDOI
Temperature-programmed reduction of CoOAI2O3 catalysts
P. Arnoldy,Jacob A. Moulijn +1 more
TL;DR: In this article, it was shown that temperature-programmed reduction (TPR) is a sensitive technique for the characterization of Co and Co-Aloxidic phases in CoOAl2O3 catalysts.
Journal ArticleDOI
In situ Mössbauer emission spectroscopy studies of unsupported and supported sulfided CoMo hydrodesulfurization catalysts: Evidence for and nature of a CoMoS phase
TL;DR: In this paper, the structure and type of phases present in sulfided alumina-supported, as well as unsupported, Co-Mo catalysts is obtained from in situ Mossbauer emission spectroscopy (MES) studies.
Journal ArticleDOI
On the catalytic significance of a CoMoS phase in CoMoAl2O3 hydrodesulfurization catalysts: Combined in situ Mössbauer emission spectroscopy and activity studies
TL;DR: In this article, a series of sulfided Co-Mo Al 2 O 3 catalysts with different Co Mo ratios but with constant molybdenum content was investigated, and it was shown that the relative amounts of the three phases depend strongly on the Co Mo ratio.
Journal ArticleDOI
An XPS and TPR study of the reduction of promoted cobalt-kieselguhr Fischer-Tropsch catalysts
TL;DR: In this paper, a mechanism of reduction based on spectroscopic measurements of the surface phases before and after H2 treatment at 400 °C was proposed, where the authors showed that the cobalt in Magnesia-promoted CoO phases is reduced completely to the metal at much higher temperatures (500-700°C) but at 400°C the surface reduction is limited to 55% ± 5 after 1 h.
Journal ArticleDOI
Active sites and support effects in hydrodesulfurization catalysts
Henrik Topsøe,Bjerne S. Clausen +1 more
TL;DR: In this article, the authors reviewed some of the current research on HDS catalysts and presented some new results, such as the nature of active sites in unpromoted and promoted HDS catalyst, the origin of promotional behaviors, studies of thermal ageing processes using high temperature sulfiding procedures, and the change in the phases present in catalysts after use under industrial conditions, and support effects in carbon and alumina-supported Co and Co-Mo catalysts.
References
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Journal ArticleDOI
Raman and ultraviolet spectroscopic characterization of molybdena on alumina/catalysts
TL;DR: In this paper, the Raman and UV spectra indicated that adsorption on the alumina surface occurred in all cases via the MoO/sub 4/(-2) ion, probably due to locally increased pH.
Journal ArticleDOI
Structure and catalytic activity of MoO3 · Al2O3 systems: I. Solid-state properties of oxidized catalysts
TL;DR: In this paper, a monolayer deposition up to about 15-20 wt% MoO3 was demonstrated for a monolingual deposition of alumina-molybdic acid complexes at the surface.
Journal ArticleDOI
Raman spectroscopic study of Co-Mo/gamma-Al2O3 catalysts
TL;DR: In this article, the structure of molybdenum and cobalt species present in CoMo γ-Al 2 O 3 (Co Mo atomic ratio, 0.64) catalyst systems was analyzed using laser Raman spectroscopy.
Journal ArticleDOI
The mechanism of pyridine hydrogenolysis on molybdenum-containing catalysts : I. The monolayer MoO3-Al2O3 catalyst: Preparation and catalytic properties
J. Sonnemans,P. Mars +1 more
TL;DR: In this paper, a MoO3-Al2O3 catalyst with a monolayer of molybdenum oxide on the alumina was shown to have a characteristic value of 17A2 for the area occupied by one MoO 3 molecule.
Journal ArticleDOI
Studies of molybdena-alumina catalysts: II. Kinetics and stoichiometry of reduction
TL;DR: In this paper, a flow microbalance reactor at atmospheric pressure was used for hydrogen reduction of molybdena-alumina catalysts, where the authors measured the extent of reduction of Mo(VI) oxide to lower valences from weight loss measurements.
Related Papers (5)
Adsorption studies on hydrodesulfurization catalysts: I. Infrared and volumetric study of NO adsorption on alumina-supported Co, Mo, and Co-Mo catalysts in their calcined state
Nan-Yu Topsøe,Henrik Topsøe +1 more