Catalytic significance of a Co-Mo-S phase in Co-Mo/Al/sub 2/O/sub 3/ hydrodesulfurization catalysts: combined in situ Moessbauer emission spectroscopy and activity studies

Journal Article · Wed Apr 01 00:00:00 EST 1981 · J. Catal.; (United States)

OSTI ID:6414535

Wivel, C ^[1]; Candia, R; Clausen, B S; Moerup, S; Topsoee, H

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1. Technical Univ. of Denmark, Lyngby

A series of sulfided Co-Mo/Al/sub 2/O/sub 3/ catalysts with different Co/Mo ratios but with constant molybdenum content is investigated. The catalysts are characterized by in situ Moessbauer emission spectroscopy (MES) and investigated for their thiophene hydrodesulfurization activity. The catalytic activity shows a pronounced maximum at a Co/Mo ratio of about 1.0. The MES spectra reveal that cobalt may be present in three distinctly different phases: cobalt located in the alumina lattice (Co:Al/sub 2/O/sub 3/), cobalt in Co/sub 9/S/sub 8/, and cobalt located in the Co-Mo-S surface phase discussed in the preceeding paper. It is found that the relative amounts of the three phases depend strongly on the Co/Mo ratio. The Co:Al/sub 2/O/sub 3/ phase and the Co-Mo-S phase are observed in all catalysts studied, whereas Co/sub 9/S/sub 8/ is observed only in catalysts with Co/Mo > 0.4. It is shown that the presence of Co/sub 9/S/sub 8/ cannot explain the promoting role of cobalt in the Co-Mo/Al/sub 2/O/sub 3/ catalysts. However, a linear relation between the catalytic activity and the amount of Co in the Co-Mo-S phase leads to the conclusion that the promoting effect of cobalt is associated with the presence of this phase.

• OSTI ID: 6414535
• Journal Information: J. Catal.; (United States), Vol. 68:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
COBALT
CATALYTIC EFFECTS
DESULFURIZATION
CATALYSTS
MOLYBDENUM
SULFIDES
ALUMINIUM OXIDES
CATALYSIS
EMISSION SPECTROSCOPY
PHASE STUDIES
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
METALS
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METALS
SPECTROSCOPY
SULFUR COMPOUNDS
TRANSITION ELEMENTS
020400* - Petroleum- Processing