Effect of boron on the state and dispersion of Co/Al/sub 2/O/sub 3/ catalysts

Journal Article · Wed Apr 01 04:00:00 EST 1987 · J. Catal.; (United States)

OSTI ID:5442080

Stranick, M A; Houalla, M; Hercules, D M

The influence of boron on the chemical state and dispersion of Co/Al/sub 2/O/sub 3/ catalysts has been investigated by bulk and surface spectroscopic techniques. Three series of Co/Al/sub 2/O/sub 3/ catalysts were studied: one containing a constant Co loading of 3 wt% and boron loading of 0.3 to 3 wt%, and two series containing 0.7 to 10 wt% Co and constant boron loadings of either 0 or 3 wt%. In the absence of boron, Co dispersion decreased with increasing Co loading above 1.5 wt% Co. The presence of boron had little effect on Co dispersion at low Co loadings, while catalysts with Co loadings in excess of 1.5 wt% exhibited an increase in Co dispersion compared to boron-free catalysts. X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, and gravimetric analysis were used to quantify the Co species present on the catalysts as a function of both Co and boron loading. In the absence of boron, Co exists as tetrahedral and octahedral Co/sup 2 +/ at low Co loadings, while Co/sub 3/O/sub 4/ is the primary phase at higher Co loadings. In the presence of boron, Co/sub 3/O/sub 4/ formation is suppressed for catalysts with Co loadings less than 8 wt% in favor of octahedral Co/sup 2 +/ and minor amounts of Co borate. The formation of Co/sub 3/O/sub 4/ occurs at Co loadings greater than 6 wt% for boron-containing catalysts. A mechanism is described to account for the effect of boron on the dispersion and chemical state of Co. 41 references.

• Research Organization: Univ. of Pittsburgh, PA
• OSTI ID: 5442080
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 104:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

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400201* -- Chemical & Physicochemical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BORON
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CATALYTIC REFORMING
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
CHEMICAL STATE
COBALT
COBALT COMPOUNDS
COBALT OXIDES
CRYSTAL STRUCTURE
DISTRIBUTION
ELECTRON SPECTROSCOPY
ELECTRONIC STRUCTURE
ELEMENTS
FISCHER-TROPSCH SYNTHESIS
GRAVIMETRIC ANALYSIS
HYDROCARBONS
METALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
QUANTITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
REFORMER PROCESSES
SEMIMETALS
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
X-RAY SPECTROSCOPY