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Title: Oxidative coupling of methane. II. Formation of active sites by lead and tin oxides on MgO

Journal Article · · Journal of Catalysis; (USA)

The oxidative coupling of methane has been studied over Sn-Mg-O catalysts with varying amounts of Sn. The addition of small amounts of tin oxide to MgO increased both the rate of methane conversion and the C{sub 2} selectivity. A maximum C{sub 2} selectivity of 40% was obtained over 0.4 at.% Sn-Mg-O at 780{degree} at a methane conversion of 20%. The maximum in C{sub 2} selectivity can be explained by considering an isolated site type mechanism in methane oxidation. According to this mechanism, an active and selective catalyst should have highly oxidizing sites isolated from each other by relatively inactive sites. Such an arrangement would allow a high methane conversion rate and the highest C{sub 2} selectivity by limiting the total oxidation of intermediates on the catalyst. A simple kinetic model based on the isolated site mechanism, which explains most of the catalytic features of the Sn-Mg-O catalytic system, has been developed. The model predicts an optimum selectivity for C{sub 2} hydrocarbons as a function of Sn content.

OSTI ID:
6350802
Journal Information:
Journal of Catalysis; (USA), Vol. 123:1; ISSN 0021-9517
Country of Publication:
United States
Language:
English