Oxidative coupling of methane over oxide-supported barium catalysts
- Texas A M Univ., College Station, TX (United States)
The effects of barium loading level and support basicity on the activity and C[sub 2+] selectivity for oxidative coupling of methane were examined for MgO-, CaO-, ZnO-, and Al[sub 2]O[sub 3]-supported Ba catalysts. The nature and distribution of catalyst surface species were characterized by XPS and ISS spectroscopic techniques, which indicated that there is no direct correlation between support basicity and oxidative coupling activity. However, catalysts containing sufficiently high Ba loadings are more easily poisoned by carbon dioxide than those with low Ba contents, due to increased stability of a BaCO[sub 3] phase. With supports of low basicity, or when the Ba is uniformly distributed on the catalyst support, the susceptibility to carbon dioxide poisoning is minimized. XPS characterization of the Ba/MgO catalysts confirmed that oxidative coupling activity is directly related to the capability of the catalyst to form surface O[sub 2][sup 2[minus]] ions existing in a BaO[sub 2] phase that is sustained under reaction conditions by the presence of molecular O[sub 2]. With a 2 mol% Ba/MgO catalyst, a C[sub 2+] selectivity of 80% at a CH[sub 4] conversion of 17% was achieved using a CH[sub 4]:O[sub 2] = 10:1 reactant mixture at 800[degrees]C and a total reagent pressure of 1 atm. 27 refs., 14 figs., 3 tabs.
- OSTI ID:
- 5771999
- Journal Information:
- Journal of Catalysis; (United States), Vol. 143:1; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
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ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
03 NATURAL GAS
10 SYNTHETIC FUELS
ALUMINIUM OXIDES
CATALYTIC EFFECTS
BARIUM
CALCIUM OXIDES
MAGNESIUM OXIDES
METHANE
COUPLING
ZINC OXIDES
CATALYST SUPPORTS
CATALYSTS
HETEROGENEOUS CATALYSIS
ION SCATTERING ANALYSIS
IONS
OXIDATION
PHOTOELECTRON SPECTROSCOPY
POISONING
STABILITY
X-RAY SPECTROSCOPY
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
ALKANES
ALUMINIUM COMPOUNDS
CALCIUM COMPOUNDS
CATALYSIS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
ELECTRON SPECTROSCOPY
ELEMENTS
HYDROCARBONS
MAGNESIUM COMPOUNDS
METALS
NONDESTRUCTIVE ANALYSIS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SPECTROSCOPY
ZINC COMPOUNDS
400201* - Chemical & Physicochemical Properties
032000 - Natural Gas- Transport
Handling
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100200 - Synthetic Fuels- Production- (1990-)