Role of group VIII metal promoter in MoS/sub 2/ and WS/sub 2/ hydrotreating catalysts. I. ESR studies of Co-Mo-Ni-Mo, and Ni-W catalysts

Journal Article · Fri Feb 01 04:00:00 EST 1985 · J. Catal.; (United States)

OSTI ID:5371629

Thakur, D S; Delmon, B

ESR spectroscopic measurements have been carried out on unsupported Co-Mo, Ni-Mo, Ni-W sulfide catalysts with two objectives: the first is to determine the role of Group VIII metal promoter atom in hydrotreating catalysts, while the second is to identify differences, if any, between Mo and W based catalysts. This study shows two ranges of promotor concentrations which deserve more attention, viz., low promotor concentration range (r = Group VIII metal atom/(Group VIII + Group VI-B) metal atoms <0.05), and high promoter concentration (0.1 < r < 0.5). The presence of trivalent Group VI-B metal species has been detected in both cases. In the low concentration range, addition of Group VIII metal atom has been found to suppress ESR signals due to defects present in the host dichalcogenide (MoS/sub 2/ or WS/sub 2/). In the region corresponding to high promoter content, strong ferromagnetic behavior is observed. These results are explained invoking current theories proposed for HDS catalysis. A comparison of ESR spectra of Mo and W catalysts shows that although paramagnetic properties of Mo-based catalysts are not very different from those exhibited by W-based catalysts and their responses to addition of Group VIII metal are quite similar, a stronger electronic interaction is observed in WS/sub 2/-based catalysts. 50 refs., 4 figs., 2 tabs.

• Research Organization: Univ. Catholigue de Louvaine, Belgium
• OSTI ID: 5371629
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 91:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical &amp; Physicochemical Properties
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
COBALT
DATA
ELECTRON SPIN RESONANCE
ELEMENTS
EXPERIMENTAL DATA
FERROMAGNETIC MATERIALS
INFORMATION
IRON
MAGNETIC MATERIALS
MAGNETIC RESONANCE
MATERIALS
METALS
MOLYBDENUM
NICKEL
NUMERICAL DATA
PROMOTERS
RESONANCE
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN