Oxidative coupling of methane on sodium aluminate- and magnesium oxide- supported samarium oxide

Abstract The oxidative coupling of methane was studied over basic and neutral oxides as well as supported Sm 2 O 3 under various reaction conditions. Among the basic and neutral oxides investigated, NaAlO 2 was found to be one of the most active and selective catalyst for C 2 hydrocarbon (ethane and ethylene) production at reaction temperatures higher than 750°C; methane conversion is 13.4% and C 2 selectivity is 63% at 800°C. These values compare favourably with those obtained from pure Sm 2 O 3 under the same reaction conditions. On the Sm 2 O 3 /MgO catalysts, a maximum percentage loading was observed for optimum total C 2 selectivity (25% Sm 2 O 3 on MgO) the activity of which is comparable with that of pure Sm 2 O 3 (calcined at 800°C). Sm 2 O 3 /NaAlO 2 catalysts also show loading dependence and, between 25–30% loading, the catalyst showed better activity and selectivity (750°C) than pure Sm 2 O 3 . Product yields on both Sm 2 O 3 /MgO and Sm 2 O 3 /NaAlO 2 catalysts were found to be stable at 815°C for over 16 hours.