W-Incorporated CoMo/{lambda}-Al{sub 2}O{sub 3} hydrosulfurization catalyst. II. Characterization

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1996.9999· OSTI ID:263788

Lee, D K; Lee, H T ^[1]

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1. Korea Institute of Energy Research, Teajon (Korea, Republic of); and others

Series of W-incorporated CoMo/{gamma}-Al{sub 2}O{sub 3} catalysts were characterized with TPR, DRS, ESR, and XPS. Two series of catalysts with varying content of tungsten were prepared for characterization by changing the impregnation order of cobalt and tungsten to a base Mo/{gamma}-Al{sub 2}O{sub 3} catalyst. The activity promotion by relatively low content of tungsten arose from the roles of tungsten in changing the Mo-oxide coordination from tetrahedral to octahedral, facilitating the reduction of Mo-oxide species, and increasing the dispersion of MoS{sub 2}. By incorporation of tungsten at a content as much as 0.025 in W/(W + Mo) atomic ratio, the MoS{sub 2} dispersion of CoMo/{gamma}-Al{sub 2}O{sub 3} catalyst was considered to be maximized without noticeable detriment to the active Co-Mo-O phase, resulting in the maximum activity promotion. The formation of the Co-Mo-O phases was more favored in the catalysts prepared by impregnating W onto CoMo/{gamma}-Al{sub 2}O{sub 3} than in those by impregnating W onto Mo/{gamma}-Al{sub 2}O{sub 3} before impregnation of Co. The effect of tungsten on the dispersion of active phase was not discriminated between the two series of catalysts. The activity decrease observed in the catalysts containing higher content of tungsten originated from the increase in the W-oxide coverage on the surface of Mo-oxides or Co-Mo-O phases, resulting in not only impeding the reduction or sulfidation of the oxidic precursor but facilitating the formation of less active Co-W-O at the sacrifice of more active Co-Mo-O phase. 40 refs., 11 figs., 1 tab.

• OSTI ID: 263788
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 159; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
40 CHEMISTRY
ALUMINIUM OXIDES
CATALYSTS
CATALYTIC EFFECTS
COBALT
CONCENTRATION RATIO
DESULFURIZATION
ELECTRON SPIN RESONANCE
HETEROGENEOUS CATALYSIS
HYDROGENATION
MOLYBDENUM
PHOTOELECTRON SPECTROSCOPY
REDUCTION
STRUCTURAL CHEMICAL ANALYSIS
TUNGSTEN
X-RAY SPECTROSCOPY