Activation of methane by clean and chemically modified single crystal oxide surfaces. Annual report, September 1991-October 1992
The oxidative coupling of methane to ethane over model MgO catalysts prepared under well-controlled, ultrahigh vacuum conditions has been studied using a combination of surface science techniques and reaction kinetic measurements. The utilization of electron energy loss spectroscopy has allowed the characterization of a variety of defects in the catalysts and the identification of the active sites which are responsible for the methane coupling reaction. A quantitative correlation between the density of specific defects and the ethane formation rate indicates that (Li(+1)O(-)) centers are not likely directly involved in the methane activation step as previously proposed. The (Li(+1)O(-)) centers, rather, promote the formation in the near-surface region of F-type centers which are responsible for the primary carbon-hydrogen bond scission reaction step. These results suggest new procedures to enhance the active site densities on Li/MgO catalysts, and thus offer a potential new approach to enhanced activities and selectivities for this class of materials.
- Research Organization:
- Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry
- OSTI ID:
- 6933535
- Report Number(s):
- PB-93-157295/XAB; RF--6888; CNN: GRI-5091-260-2182
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
100200* -- Synthetic Fuels-- Production-- (1990-)
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALKANES
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION YIELD
CONVERSION
COUPLING
DEFECTS
DENSITY
ELECTROMAGNETIC RADIATION
ENERGY SOURCES
ETHANE
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
HYDROCARBONS
KINETICS
LITHIUM COMPOUNDS
LITHIUM OXIDES
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
METHANE
NATURAL GAS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUANTIZATION
RADIATIONS
REACTION KINETICS
RESEARCH PROGRAMS
SPECTROSCOPY
SURFACE PROPERTIES
SURFACES
ULTRAHIGH VACUUM
YIELDS