(704h) Effect of Dopants on the Activity and Selectivity in the Oxidative Coupling of Methane over Rare Earth Oxides
AIChE Annual Meeting
2018 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Fundamentals of Catalysis III: Oxidation in Supported Catalysis
Thursday, November 1, 2018 - 5:36pm to 5:54pm
The oxidative coupling of methane (OCM) is a potential pathway to convert methane directly to highly valuable ethylene, as well as other hydrocarbon products. However, it is very difficult to obtain high yields of C2+ products (i.e. products such as ethane, ethylene and higher hydrocarbons), due to the formation of thermodynamically more stable higher oxidation products, such as CO and CO2 (COx). It is well known that rare earth oxides (REOs), such as samaria (Sm2O3) and lanthana (La2O3), are amongst the most efficient single component oxide catalysts in the oxidative coupling of methane, while reducible REOs (e.g. ceria, terbia, and praseodymia) are typically more selective towards COx products than C2+ products. However, we have in the past shown that addition of lithium to non-reducible rare earth oxides can significantly alter their activity and selectivity in the OCM reaction. For example, Li-doped terbia supported on MgO is not only more active and selective compared with the reference Li/MgO, Sm2O3/MgO and Li-Sm2O3/MgO catalysts, it is also more stable in the OCM reaction with time on stream. We have extended the investigation of doped rare earth oxides to include also transition metal dopants and report their effects on the OCM reaction.