Chemical and catalytic activation of methane by metal oxide surfaces. Annual report, September 1989-August 1990. [Iron and manganese perovskites]

Technical Report · Mon Jun 01 04:00:00 EDT 1992

OSTI ID:6834554

McCarty, J G; Wachsman, E D

The objectives of the research are to investigate the nature of surface oxygen centers capable of selective conversion of methane into hydrocarbon fuels through catalytic selective oxidation and to determine the role of homogeneous reactions in the catalytic coupling process. Major accomplishments of the current work include the development of stable redox coupling catalysts and the identification of impurity metals in alkaline earth catalysts. The authors explored the ability of lanthana-based iron and manganese perovskites to serve as selective redox catalysts. The authors' results indicate that protective alkali or alkaline earth layers are necessary for these transition metal perovskites to have acceptable higher hydrocarbon selectivity. Oxygen transfer clearly did not limit the reactivity of these catalyst/reactants under coupling conditions. Sensitive surface analysis of calcined CaO and MgO alkaline earth and zirconia co-oxidative methane dimerization catalysts by laser ionization (SALI) showed unexpectedly high levels (to approx 1000 ppm) of segregated base metals, especially iron. Catalysts with higher iron levels had poorer higher hydrocarbon selectivity and higher carbon dioxide to carbon monoxide product ratios. The authors conclude that the impurity segregated metal cations, by atracting excess reducible oxygen to the surfaces, cause the poorer performance of CaO and MgO relative to alkali oxide catalysts.

• Research Organization: SRI International, Menlo Park, CA (United States)
• OSTI ID: 6834554
• Report Number(s): PB-93-121994/XAB; CNN: GRI-5086-260-1328
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
100200* -- Synthetic Fuels-- Production-- (1990-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKANES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC EFFECTS
CATIONS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL ACTIVATION
CHEMICAL REACTIONS
CONVERSION
DIMERIZATION
ELEMENTS
FUELS
HYDROCARBONS
IONS
IRON
KINETICS
MANGANESE
METALS
METHANE
NONMETALS
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PARTIAL OXIDATION PROCESSES
PERFORMANCE
PEROVSKITES
POLYMERIZATION
REACTION KINETICS
SURFACE PROPERTIES
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENTS