Oxidative coupling of methane over La sub 2 O sub 3 -CaO catalysts: Effect of bulk and surface properties on catalytic performance

Journal Article · Mon Apr 01 00:00:00 EST 1991 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(91)90308-Q· OSTI ID:5721040

Becker, S; Baerns, M ^[1]

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1. Ruhr-Universitat Bochum (Germany)

The oxidative coupling reaction of methane to higher hydrocarbons over lanthanum-calcium-oxide catalysts was studied in a microcatalytic fixed-bed reactor in the temperature range from 973 to 1013 K applying inlet partial pressures of methane and oxygen of 93 and 7 kPa, respectively. Lanthanum to calcium atom ratios of the catalyst were varied as follows: 0/100,1/99,5/95,10/90,14/86,20/80,27/73/,50/50,70/30,and 100/0. Maximum C{sub 2+} selectivities of 76% and C2+ yields of 9% were achieved (1013 K). The bulk-phase and surface compositions of the catalysts were determined by XRD and XPS, respectively. A relative measure of surface basicity and acidity was derived from the product distribution of the isopropyl alcohol conversion used as a probe reaction. The catalytic performance of the differently composed materials is affected by their surface composition and not by their bulk composition. Maximum selectivity is achieved with a surface content of lanthanum between 60 and 90%. It is tentatively suggested that a catalyst which is primarily basic in nature requires acidic sites also for achieving high C{sub 2+} selectivity.

• OSTI ID: 5721040
• Journal Information: Journal of Catalysis; (USA), Vol. 128:2; ISSN 0021-9517
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
CALCIUM OXIDES
CATALYTIC EFFECTS
SURFACE PROPERTIES
LANTHANUM OXIDES
METHANE
CATALYTIC REFORMING
OXIDATION
CATALYSTS
CHEMICAL COMPOSITION
CHEMICAL REACTION YIELD
ETHANE
ETHYLENE
PH VALUE
PHOTOELECTRON SPECTROSCOPY
PROPANOLS
QUANTITY RATIO
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
ALCOHOLS
ALKALINE EARTH METAL COMPOUNDS
ALKANES
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CALCIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
DIFFRACTION
ELECTRON SPECTROSCOPY
HYDROCARBONS
HYDROXY COMPOUNDS
LANTHANUM COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
REFORMER PROCESSES
SCATTERING
SPECTROSCOPY
YIELDS
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