Influence of lanthanum on the surface structure and CO hydrogenation activity of supported cobalt catalysts

Journal Article · Thu Sep 07 04:00:00 EDT 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100355a039· OSTI ID:7246576

Ledford, J S; Houalla, M; Proctor, A; Hercules, D M ^[1]; Petrakis, L ^[2]

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1. Univ. of Pittsburgh, PA (USA)
2. Gulf Research and Development, Pittsburgh, PA (USA)

X-ray photoelectron spectroscopy (ESCA or XPS), X-ray diffraction (XRD), Raman spectroscopy, H{sub 2} chemisorption, and gravimetric analysis have been used to characterize three series of La/Al{sub 3}O{sub 3} and CoLa/Al{sub 2}O{sub 3} catalysts. CoLa/Al{sub 2}O{sub 3} catalysts were prepared by two methods: impregnation of La first followed by Co (designated CoLay) and impregnation of Co first followed by La (designated LayCo). The information obtained from surface and bulk characterization has been compared with CO hydrogenation activity and selectivity of the supported Co/Al{sub 2}O{sub 3} catalysts. For CoLay catalysts with low La loadings (La/Al atomic ratio {le} 0.026), the presence of La had little effect on the structure or CO hydrogenation activity. However, the selectivity to higher hydrocarbons and olefinic products increased with increasing La content. For CoLay catalysts with higher La loadings, Co{sub 3}O{sub 4} is suppressed in favor of an amorphous dispersed La-Co mixed oxide. ESCA and H{sub 2} chemisorption indicated higher dispersion of the metallic cobalt phase for high La loadings. The turnover frequency (TOF) for CO hydrogenation decreased dramatically for high La loadings. This has been correlated to the decrease in the amount of Co{sub 3}O{sub 4} present in the La-rich catalysts. Catalysts prepared by reverse impregnation (LayCo) showed little evidence of La-Co interaction. No significant variation in reducibility or cobalt metal dispersion was observed. Lanthanum addition had little effect on the TOF for CO hydrogenation or the selectivity to olefinic products and higher hydrocarbons.

• OSTI ID: 7246576
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:18; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360000 -- Materials
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400000* -- Chemistry
400200 -- Inorganic
Organic
& Physical Chemistry
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
COBALT
DATA
DATA ANALYSIS
ELEMENTS
EXPERIMENTAL DATA
HYDROGENATION
INFORMATION
LANTHANUM
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
RARE EARTHS
SEPARATION PROCESSES
SORPTION
SURFACE PROPERTIES
TRANSITION ELEMENTS