The active phase in sodium-doped calcium oxide catalysts for oxidative coupling of methane

• Published in: Journal of catalysis Vol. 128; no. 1; pp. 264 - 274
• Main Authors: Peng, X.D, Stair, P.C
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.03.1991; Elsevier
• Subjects: 03 NATURAL GAS; 030300 - Natural Gas- Drilling, Production, & Processing; ALKALI METALS; ALKALINE EARTH METAL COMPOUNDS; ALKANES; ALKENES; CALCIUM CARBONATES; CALCIUM COMPOUNDS; CALCIUM OXIDES; CARBON COMPOUNDS; CARBONATES; CATALYSIS; Catalysts: preparations and properties; CATALYTIC EFFECTS; CATALYTIC REFORMING; CHALCOGENIDES; CHEMICAL REACTIONS; Chemistry; DEACTIVATION; DOPED MATERIALS; ELEMENTS; ETHANE; ETHYLENE; Exact sciences and technology; General and physical chemistry; HYDROCARBONS; MATERIALS; METALS; METHANE; ORGANIC COMPOUNDS; OXIDATION; OXIDES; OXYGEN COMPOUNDS; PROMOTERS; REFORMER PROCESSES; SODIUM; SURFACE PROPERTIES; SYNTHESIS; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Calcium Oxides; Selectivity; Deactivation; Doping; Sodium Alkali metal
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/0021-9517(91)90082-F

The reactivity of pure and sodium-promoted calcium oxide catalysts toward the oxidative coupling of methane at 640°C has been investigated. While the pure calcium oxide was essentially a combustion catalyst, sodium-promoted calcium oxide exhibited significant C 2 productivity. Study of the deactivation of both pure and promoted catalysts demonstrated that the presence of calcium oxide was necessary for both catalysts to be active. This observation, combined with the effects of sodium doping on C 2 selectivity, suggests that the active phase on Na/CaO catalysts toward C 2 formation consists of sodium species associated with calcium oxide. This active phase was destroyed when calcium oxide was converted into calcium carbonate under reaction conditions.